webadmin: Added translation for import cluster errors

If there are any errors while fetching the gluster servers
to import, the error message from the server will be
translated and shown to the user.

Change-Id: I0a42f4d46dea10485ea1864deeddf66483fd8241
Bug-Url: https://bugzilla.redhat.com/884292
Signed-off-by: Kanagaraj M <kmayilsa@redhat.com>