overwriteIfNewer forces not needed overwrite of already existing artifacts

The <overwriteIfNever/> property does not work for classifier <classifier>sources</classifier> . As soon as the overWriteIfNever property is enabled, the artifacts with classifier "sources" are always overwritten. So not needed files are written very often to the disk.

The flag seems to work as expected for executions where no classifier is specified.

See the attached sample project where execution "thirdparty" can handle overwriteIfNever correctly. While the execution "thirdparty.sources" always copies files to the disk:

[INFO] --- maven-dependency-plugin:2.9-SNAPSHOT:copy-dependencies (thirdparty) @ ch.ivyteam.testarea.overwrite ---
[INFO] junit:junit:jar:3.8.1 already exists in destination.
[INFO] 
[INFO] --- maven-dependency-plugin:2.9-SNAPSHOT:copy-dependencies (thirdparty.sources) @ ch.ivyteam.testarea.overwrite ---
[INFO] Copying junit-3.8.1-sources.jar to D:\dev\trunk\real_workspaceKepler\ch.ivyteam.testarea.overwrite\lib\mvn-src\junit-3.8.1-sources.jar

The not yet released version 2.9 in use was: maven-dependency-plugin-2.9-20140907.174645-631