glusterd: Handle rpc_connect failure in the event handler

Currently rpc_connect calls the notification function on failure in the
same thread, glusterd notification holds the big_lock and
hence big_lock is released before rpc_connect

In snapshot creation, releasing the big-lock before completeing
operation can cause problem like deadlock or memory corruption.

Bricks are started as part of snapshot created operation.
brick_start releases the big_lock when doing brick_connect and this
might cause glusterd crash.
There is a similar issue in bug# 1088355.

Solution is let the event handler handle the failure than doing it in
the rpc_connect.

Change-Id: I088d44092ce845a07516c1d67abd02b220e08b38
BUG: 1101507
Signed-off-by: Vijaikumar M <vmallika@redhat.com>
Reviewed-on: http://review.gluster.org/7843
Reviewed-by: Krishnan Parthasarathi <kparthas@redhat.com>
Reviewed-by: Jeff Darcy <jdarcy@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Raghavendra G <rgowdapp@redhat.com>
Tested-by: Raghavendra G <rgowdapp@redhat.com>