Drop extra review note when doing certain operations via SSH

Abandon via SSH always created two comments for a change, 'review note' and
'abandon comment'. Same happened with defer and restore operations. Example
command and output below:

  'ssh demosrv gerrit review --abandon -m "Example comment" sha1'
  Review note:     'Patch Set 3: Example comment'
  Abandon comment: 'Abandoned Example comment'

This is not what one would expect to happen. One comment is enough and
'abandon comment' would be the preferred one. Just like it happens via UI.
This is what this patch does. 'Review note' is dropped and just 'abandon
comment' is kept. Same goes for defer and restore.

  'ssh demosrv gerrit review --abandon -m "Comment fixed" sha1'
  Abandon comment: 'Abandoned Comment fixed'

'Review note' is necessary just when labels (review scores) are applied.
So with review labels applied, this patch changes nothing:

  'ssh demosrv gerrit review --abandon -m "Comment" sha1 -l Sanity-Review=0'
  Review note:     'Patch Set 3: -Sanity-Review Comment'
  Abandon comment: 'Abandoned'

In this case 'abandon comment' is simply 'abandoned' and has no scores neither
given message included.

Task-number: QTQAINFRA-886
Change-Id: I790caa91df603748139881b123da0072fea6dd74
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>
Reviewed-by: Ismo Haataja <ismo.haataja@digia.com>