gluster: fix remove-bricks error messages

Corrected the error messages for start/stop/commit remove-bricks
operation and added missing entries.

Change-Id: I2ac00b5cb111bbdbae20b7b87e1b727a26720ef7
Bug-Url: https://bugzilla.redhat.com/1044598
Signed-off-by: Kanagaraj M <kmayilsa@redhat.com>