Add trustrpid and sendrpid global values to 'sip show settings'

(closes issue #17860)
Reported by: jtodd
Patches:
      __20100816-chan_sip-sip-show-settings.txt uploaded by lmadsen (license 10)
Tested by: lmadsen, russell

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@284315 65c4cc65-6c06-0410-ace0-fbb531ad65f3