Fix FT build of nuxeo-imap-connector

10:36:14 /opt/jenkins/workspace/addons_FT_nuxeo-imap-connector-master/ftest/webdriver/itests.xml:21: java.lang.NullPointerException
10:36:14 	at org.nuxeo.build.maven.graph.DependencyUtils.setNewestVersion(DependencyUtils.java:213)
10:36:14 	at org.nuxeo.build.ant.artifact.ResolveFile.resolveFile(ResolveFile.java:83)
10:36:14 	at org.nuxeo.build.ant.artifact.ResolveFile.getFile(ResolveFile.java:99)
10:36:14 	at org.apache.tools.ant.types.resources.FileResource.getNotNullFile(FileResource.java:369)
10:36:14 	at org.apache.tools.ant.types.resources.FileResource.isExists(FileResource.java:179)
10:36:14 	at org.apache.tools.ant.taskdefs.Copy.execute(Copy.java:519)
10:36:14 	at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:292)
10:36:14 	at sun.reflect.GeneratedMethodAccessor45.invoke(Unknown Source)
10:36:14 	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
10:36:14 	at java.lang.reflect.Method.invoke(Method.java:606)
10:36:14 	at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
10:36:14 	at org.apache.tools.ant.Task.perform(Task.java:348)
10:36:14 	at org.apache.tools.ant.Target.execute(Target.java:435)
10:36:14 	at org.apache.tools.ant.Target.performTasks(Target.java:456)
10:36:14 	at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1393)
10:36:14 	at org.apache.tools.ant.Project.executeTarget(Project.java:1364)
10:36:14 	at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)
10:36:14 	at org.nuxeo.build.ant.AntClient.run(AntClient.java:162)
10:36:14 	at org.nuxeo.build.maven.AntBuildMojo.execute(AntBuildMojo.java:256)