copy-dependencies + copyPom + useRepositoryLayout skips existing artifacts

copy-dependencies using copyPom with useRepositoryLayout will skip copying poms to artifact directories that already exist. This doesn't seem to happen without useRepositoryLayout

Here is a link to a bash script demonstrating the bug. It clones apache commons-math, and then copies its dependencies with useRepositoryLayout. It then goes back and does it with copyPom=true, but the pom files do not get copied.

This can be overcome by setting -DoverWriteReleases=true

https://gist.github.com/olemma/2a344a5748befcb7acce