cli: Fix remove brick cli out for wrong volume name

Problem:  gluster volume remove-brick command, was not printing the error in
          case of volume-name specified is wrong.

Fix:      Fix will print error message to indicate that provided volume name is
          invalid. Although patch for bug 961669
          http://review.gluster.org/#/c/4975/ does print cli-output now, but
          still xml is unable to use the response values

Change-Id: I2ee1df86c1e756fb8e93b4d6bbdd102b4f368f87
BUG: 961307
Signed-off-by: Venkatesh Somyajulu <vsomyaju@redhat.com>
Reviewed-on: http://review.gluster.org/4972
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>