Fix target platforms tests when using different timezone

    org.nuxeo.targetplatforms.io.test.TestJsonExporter.testTargetPlatformExport
    org.nuxeo.targetplatforms.io.test.TestJsonExporter.testTargetPlatformInfoExport
    org.nuxeo.targetplatforms.io.test.TestJsonExporter.testTargetPlatformInstanceExport
    org.nuxeo.targetplatforms.io.test.TestJsonExporter.testTargetPlatformsExport
    org.nuxeo.targetplatforms.io.test.TestJsonExporter.testTargetPlatformsInfosExport

java.lang.AssertionError: releaseDate
Expected: 1379887200000
     got: 1379894400000

	at org.skyscreamer.jsonassert.JSONAssert.assertEquals(JSONAssert.java:222)
	at org.skyscreamer.jsonassert.JSONAssert.assertEquals(JSONAssert.java:192)
	at org.nuxeo.targetplatforms.io.test.TestJsonExporter.checkJsonEquals(TestJsonExporter.java:111)
	at org.nuxeo.targetplatforms.io.test.TestJsonExporter.testTargetPlatformExport(TestJsonExporter.java:124)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
	at org.nuxeo.runtime.test.runner.FeaturesRunner$InvokeMethod.evaluate(FeaturesRunner.java:446)
	at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
	at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:76)
	at org.nuxeo.runtime.test.runner.FeaturesRunner.runChild(FeaturesRunner.java:401)
	at org.nuxeo.runtime.test.runner.FeaturesRunner.runChild(FeaturesRunner.java:55)
	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:366)
	at org.apache.maven.surefire.junit4.JUnit4Provider.execute(JUnit4Provider.java:264)
	at org.apache.maven.surefire.junit4.JUnit4Provider.executeTestSet(JUnit4Provider.java:153)
	at org.apache.maven.surefire.junit4.JUnit4Provider.invoke(JUnit4Provider.java:124)
	at org.apache.maven.surefire.booter.ForkedBooter.invokeProviderInSameClassLoader(ForkedBooter.java:200)
	at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:153)
	at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:103)