res/res_hep_rtcp: Remove dependency on PJSIP

The res_hep_rtcp module was incorrectly including <pjsip.h>. This didn't need
to be included, as the module does not using PJPROJECT any fashion.
Unfortunately, because res_hep_rtcp did not include pjsip in its MODULEINFO as
a dependency, this also meant that res_hep_rtcp will fail to compile on a
system without PJPROJECT.

This patch removes the include.

Thanks to Damien Wedhorn for pointing this out in #asterisk-dev.

ASTERISK-24236 #close
Reported by: Damien Wedhorn, Matt Jordan
Tested by: Damien Wedhorn
........

Merged revisions 421064 from http://svn.asterisk.org/svn/asterisk/branches/12
........

Merged revisions 421065 from http://svn.asterisk.org/svn/asterisk/branches/13


git-svn-id: http://svn.asterisk.org/svn/asterisk/trunk@421066 f38db490-d61c-443f-a65b-d21fe96a405b