pgsql: Fix crash if LockErrorCleanup() is called twice

Fix crash if LockErrorCleanup() is called twice

The refactoring in commit 3c0fd64fec removed the clearing of
awaitedLock from LockErrorCleanup(). It's still needed, otherwise
LockErrorCleanup() during abort processing will try to update the
LOCALLOCK struct even after the lock has already been released. Put it
back.

Reported-by: Richard Guo <guofenglinux(at)gmail(dot)com>
Reported-by: Robins Tharakan <tharakan(at)gmail(dot)com>
Reported-by: Alexander Lakhin <exclusion(at)gmail(dot)com>
Discussion: https://www.postgresql.org/message-id/flat/CAMbWs4_dNX1SzBmvFdoY-LxJh_4W_BjtVd5i008ihfU-wFF=eg(at)mail(dot)gmail(dot)com
Discussion: https://www.postgresql.org/message-id/18832-38e5575b1bbd7277@postgresql.org
Discussion: https://www.postgresql.org/message-id/e11a30e5-c0d8-491d-8546-3a1b50c10ad4@gmail.com

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/51a0382e8d8793b5cc89b69285e5ecdffe03c2bf

Modified Files
--------------
src/backend/storage/lmgr/lock.c | 9 +++++++++
src/backend/storage/lmgr/proc.c | 2 ++
src/include/storage/lock.h | 1 +
3 files changed, 12 insertions(+)