phabricator: move extension from contrib to hgext
It's well-enough tested now and widely enough used I think we should
ship it.
Differential Revision: https://phab.mercurial-scm.org/D4602
#require serve
$ hg clone http://localhost:$HGPORT/ copy
abort: * (glob)
[255]
$ test -d copy
[1]
$ $PYTHON "$TESTDIR/dumbhttp.py" -p $HGPORT --pid dumb.pid
$ cat dumb.pid >> $DAEMON_PIDS
$ hg clone http://localhost:$HGPORT/foo copy2
abort: HTTP Error 404: * (glob)
[255]
$ killdaemons.py