chan_sip+CEL: Add missing ANSWER and PICKUP events to INVITE/w/replaces pickup.

When doing a "BLF-style call pickup" -- an INVITE with Replaces: header -- the
CEL log would lack the ANSWER and PICKUP events.

This patch adds the two missing events to the handle_invite_replaces() function.

ASTERISK-22977 #close
Review: https://reviewboard.asterisk.org/r/3073/
........

Merged revisions 413832 from http://svn.asterisk.org/svn/asterisk/branches/1.8


git-svn-id: http://svn.asterisk.org/svn/asterisk/branches/11@413838 f38db490-d61c-443f-a65b-d21fe96a405b