res_rtp_asterisk: Fix building when pjproject is not used.


git-svn-id: http://svn.asterisk.org/svn/asterisk/branches/11@423207 f38db490-d61c-443f-a65b-d21fe96a405b
res_rtp_asterisk: Fix 100% CPU usage due to timer heap thread spinning.

Side note: I need a vacation.


git-svn-id: http://svn.asterisk.org/svn/asterisk/branches/11@423210 f38db490-d61c-443f-a65b-d21fe96a405b