D15871: Add a specific error string for ENOTEMPTY return code in SMB slave.

[Kai Uwe Broulik]

broulik added a reviewer: sitter.

REPOSITORY
  R320 KIO Extras

REVISION DETAIL
  https://phabricator.kde.org/D15871

To: madcatx, elvisangelaccio, sitter
Cc: kde-frameworks-devel, kfm-devel, feverfew, michaelh, spoorun, 
navarromorales, firef, ngraham, andrebarros, bruns, emmanuelp