We try to keep the system running even when all available memory is
spent.

Review: https://reviewboard.asterisk.org/r/2734/
........

Merged revisions 396279 from http://svn.asterisk.org/svn/asterisk/branches/1.8


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/11@396287 65c4cc65-6c06-0410-ace0-fbb531ad65f3