Fix launching of webdriver tests with FF 19

java.lang.NoClassDefFoundError: org/apache/http/entity/ContentType
	at org.openqa.selenium.remote.HttpCommandExecutor$EntityWithEncoding.<init>(HttpCommandExecutor.java:405)
	at org.openqa.selenium.remote.HttpCommandExecutor.execute(HttpCommandExecutor.java:300)
	at org.openqa.selenium.firefox.internal.NewProfileExtensionConnection.execute(NewProfileExtensionConnection.java:133)
	at org.openqa.selenium.firefox.FirefoxDriver$LazyCommandExecutor.execute(FirefoxDriver.java:355)
	at org.openqa.selenium.remote.RemoteWebDriver.execute(RemoteWebDriver.java:527)
	at org.openqa.selenium.remote.RemoteWebDriver.startSession(RemoteWebDriver.java:216)
	at org.openqa.selenium.remote.RemoteWebDriver.<init>(RemoteWebDriver.java:111)
	at org.openqa.selenium.firefox.FirefoxDriver.<init>(FirefoxDriver.java:188)
	at org.openqa.selenium.firefox.FirefoxDriver.<init>(FirefoxDriver.java:183)
	at org.openqa.selenium.firefox.FirefoxDriver.<init>(FirefoxDriver.java:179)
	at org.openqa.selenium.firefox.FirefoxDriver.<init>(FirefoxDriver.java:92)
	at org.nuxeo.runtime.test.runner.web.BrowserFamily$FirefoxDriverFactory.createDriver(BrowserFamily.java:53)
	at org.nuxeo.runtime.test.runner.web.Configuration.createDriver(Configuration.java:57)
	at org.nuxeo.runtime.test.runner.web.Configuration.getDriver(Configuration.java:101)
	at org.nuxeo.runtime.test.runner.web.WebDriverFeature$3.get(WebDriverFeature.java:121)
	at com.google.inject.internal.InternalFactoryToProviderAdapter.get(InternalFactoryToProviderAdapter.java:40)
	at com.google.inject.internal.ProviderToInternalFactoryAdapter$1.call(ProviderToInternalFactoryAdapter.java:46)
	at com.google.inject.internal.InjectorImpl.callInContext(InjectorImpl.java:1031)
	at com.google.inject.internal.ProviderToInternalFactoryAdapter.get(ProviderToInternalFactoryAdapter.java:40)
	at com.google.inject.Scopes$1$1.get(Scopes.java:65)
	at com.google.inject.internal.InternalFactoryToProviderAdapter.get(InternalFactoryToProviderAdapter.java:40)
	at com.google.inject.internal.SingleFieldInjector.inject(SingleFieldInjector.java:53)
	at com.google.inject.internal.MembersInjectorImpl.injectMembers(MembersInjectorImpl.java:110)
	at com.google.inject.internal.ConstructorInjector.construct(ConstructorInjector.java:94)
	at com.google.inject.internal.ConstructorBindingImpl$Factory.get(ConstructorBindingImpl.java:254)
	at com.google.inject.internal.InjectorImpl$4$1.call(InjectorImpl.java:978)
	at com.google.inject.internal.InjectorImpl.callInContext(InjectorImpl.java:1024)
	at com.google.inject.internal.InjectorImpl$4.get(InjectorImpl.java:974)
	at com.google.inject.internal.InjectorImpl.getInstance(InjectorImpl.java:1013)
	at org.nuxeo.runtime.test.runner.FeaturesRunner.createTest(FeaturesRunner.java:279)
	at org.junit.runners.BlockJUnit4ClassRunner$1.runReflectiveCall(BlockJUnit4ClassRunner.java:251)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
	at org.junit.runners.BlockJUnit4ClassRunner.methodBlock(BlockJUnit4ClassRunner.java:248)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:76)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
	at org.nuxeo.runtime.test.runner.FeaturesRunner.run(FeaturesRunner.java:262)
	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
	at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: java.lang.ClassNotFoundException: org.apache.http.entity.ContentType
	at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
	... 48 more