Add token callback for recovery.

gmi.h:
  Add token callback functions to header.
gmi.c:
  Add token callback for recovery routines.

BKrev: 4159aa0ejs1nwJhT7hT1XL-gr9wv2Q


git-svn-id: http://svn.fedorahosted.org/svn/corosync/trunk@297 fd59a12c-fef9-0310-b244-a6a79926bd2f