Violations plugin fails on checkstyle Translation missing check

Checkstyle can run a Translation check, and verify that certain translation property files exists.

When one is missing checkstyle outputs:

```
[ERROR] src/main/resources:[0] (misc) Translation: Properties file 'xx-messages.properties' is missing.
```

and the corresponding xml looks like:

``` xml

```

Then the violations plugin tries to read the directory "/xx/trunk/src/main/resources" as a file, and craps out:

```
WARNING: Publisher 'Report Violations' aborted due to exception:
java.io.IOException: remote file operation failed: /xx at hudson.remoting.Channel@34353fca:xx-03: java.io.FileNotFoundException: /xx/src/test/resources (Is a directory)
at hudson.FilePath.act(FilePath.java:987)
at hudson.FilePath.act(FilePath.java:969)
at hudson.plugins.violations.ViolationsPublisher.perform(ViolationsPublisher.java:74)
at hudson.tasks.BuildStepMonitor$3.perform(BuildStepMonitor.java:45)
at hudson.model.AbstractBuild$AbstractBuildExecution.perform(AbstractBuild.java:779)
at hudson.model.AbstractBuild$AbstractBuildExecution.performAllBuildSteps(AbstractBuild.java:726)
at hudson.maven.MavenModuleSetBuild$MavenModuleSetBuildExecution.post2(MavenModuleSetBuild.java:1047)
at hudson.model.AbstractBuild$AbstractBuildExecution.post(AbstractBuild.java:671)
at hudson.model.Run.execute(Run.java:1766)
at hudson.maven.MavenModuleSetBuild.run(MavenModuleSetBuild.java:531)
at hudson.model.ResourceController.execute(ResourceController.java:98)
at hudson.model.Executor.run(Executor.java:408)
```