transplant: use peer of source repository as "remote" for "repo.pull()"
Before this patch, transplant with "--merge" option fails with
traceback unexpectedly, if it causes pull from the source repository
on the local host.
"discovery.findcommonincoming()" invokes "capable()" method on the
object given from "localrepository.pull()", but it is
"localrepository" object in this case and doesn't have such method.
This patch uses peer object of source repository as "remote" argument
for "localrepository.pull()" invocation like other invocations of it
in transplant.py.
Minimal hgk check
$ echo "[extensions]" >> $HGRCPATH
$ echo "hgk=" >> $HGRCPATH
$ hg init repo
$ cd repo
$ echo a > a
$ hg ci -Am adda
adding a
$ hg debug-cat-file commit 0
tree a0c8bcbbb45c
parent 000000000000
author test 0 0
revision 0
branch default
phase draft
adda
$ cd ..