Fix of dependecies of UF:V:shell

Fix of typo in dependecies.

U:D:preferredShells wasn't in dependencies of UF:V:shell therefore if
U:D:preferredShells changed, core wasn't notified about possible change
of UF:V:shell.
Fix of typo in attributes description

Changes to be made in production instance:
Chnge description of U:D:preferredShells and UF:V:shell according to
corresponding modules.