Add "autoframing" option to sip.conf.sample and h323.conf.sample.

The autoframing option was added to chan_sip.c in r43243 (mogorman,
2006-09-19 01:32:57), but never made its way into the sample configs.

Review: https://reviewboard.asterisk.org/r/2768/
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Merged revisions 396994 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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Merged revisions 396995 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@396996 65c4cc65-6c06-0410-ace0-fbb531ad65f3