DirSupport move simplification

The "fallback" was needed only in one case, when
a dir was moved to it's subdir. But, to achieve
that one must declare excludeFilter. Hence,
from now on, WITHOUT filter that is impossible,
and in the same time, other IOEx from Files.move
should not be swallowed (ie. move over non-empty dir)
Split the method in two: move and pseudoMove
Merge remote-tracking branch 'origin/nexus-2.11.x' into nexus-2.11.x-dirsupport-move-simplification
Rename method
Merge pull request #772 from sonatype/nexus-2.11.x-dirsupport-move-simplification

[2.11.x] DirSupport.move simplification