Handle eqlx SSH connection close on abort.

EqualLogic array CLI operation timeout causes the
SSH thread to be aborted. This would cause SSH
sessions to be orphaned and hit a max connection
limit on the array. This fix catches these aborts
and makes sure the connection is closed.

Change-Id: I9392fd5dd79eb44f252bf50217f17cc473e6f2f0
Closes-Bug: 1374613
(cherry picked from commit 5cb23b67c53437fc51a6b37acac477fba4d6a7ab)
Merge "Handle eqlx SSH connection close on abort." into proposed/juno