Add a new global and per-peer option to chan_sip, qualifyfreq, which allows you

to set the qualify frequency.

(closes issue #11597)
Reported by: wilder
Patches:
      qualifyfreq5.patch uploaded by wilder (license 362)
	   -- with some mods by me


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@98027 65c4cc65-6c06-0410-ace0-fbb531ad65f3