res_pjsip: Add the ability to configure ciphers based on name.

Previously this code would only accept the OpenSSL identifier instead
of the documented name.

ASTERISK-23498 #close
ASTERISK-23498 #comment Reported by: Anthony Messina

Review: https://reviewboard.asterisk.org/r/3491/
........

Merged revisions 413159 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@413160 65c4cc65-6c06-0410-ace0-fbb531ad65f3