DLM: Eliminate CF_CONNECT_PENDING flag

Before this patch, there was a flag in the con structure that was
used to determine whether or not a connect was needed. The bit was
set here and there, and cleared here and there, so it left some
race conditions: the bit was set, work was queued, then the worker
cleared the bit, allowing someone else to set it while the worker
ran. For the most part, this worked okay, but we got into trouble
if connections were lost and it needed to reconnect.

This patch eliminates the flag in favor of simply checking if we
actually have a sock pointer while protected by the mutex.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Reviewed-by: Tadashi Miyauchi <miyauchi@toshiba-tops.co.jp>
Signed-off-by: David Teigland <teigland@redhat.com>