ORNL-28: Solve reconnecting race between IR and SR

ORNL-28: Solve reconnecting race between IR and SR

if there is a connecting request on the fly when client import is
notified by IR, it will set the corresponding conn uuid to a higher
prio and set imp_force_verify so that it will do reconnection
immediately in case RPC timeout happens.

Change-Id: I77e799e1f12b49f3c0271585c1ce812d16dc1ef6
Signed-off-by: Jinshan Xiong <jay@whamcloud.com>
Reviewed-on: http://review.whamcloud.com/1291
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>