bash completion: Add --snap lookup
bash completion: Add --snap lookup

If the fs is present in the comman line already we will fetch the
snapshots for that file system to present to the user.

Signed-off-by: Tony Asleson <1ef2d381aa56d512126ddaacc29e68136e4fdf55@redhat.com>

cathay4t/libstoragemgmt,libstorage/libstoragemgmt,tasleson/libstoragemgmt,jumitche/libstoragemgmt,libstorage/libstoragemgmt,lazy404/libstoragemgmt,HP-Scale-out-Storage/libstoragemgmt,lazy404/libstoragemgmt,tasleson/libstoragemgmt,libstorage/libstoragemgmt,tasleson/libstoragemgmt,jumitche/libstoragemgmt,joehandzik/libstoragemgmt,HP-Scale-out-Storage/libstoragemgmt,libstorage/libstoragemgmt,joehandzik/libstoragemgmt,tasleson/libstoragemgmt,HP-Scale-out-Storage/libstoragemgmt,cathay4t/libstoragemgmt,jumitche/libstoragemgmt,lazy404/libstoragemgmt,cathay4t/libstoragemgmt,HP-Scale-out-Storage/libstoragemgmt,joehandzik/libstoragemgmt,libstorage/libstoragemgmt,tasleson/libstoragemgmt,lazy404/libstoragemgmt,jumitche/libstoragemgmt,cathay4t/libstoragemgmt,joehandzik/libstoragemgmt,jumitche/libstoragemgmt,cathay4t/libstoragemgmt