Simple lock, assignment, unlock sandwich optimization.

git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@390439 f38db490-d61c-443f-a65b-d21fe96a405b
Add BUGBUG comment.

git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@390440 f38db490-d61c-443f-a65b-d21fe96a405b