tests/test-debugrename

Fix income/pull with bundle and -R (issue 820).

Uses ui.setconfig() to tell bundlerepo where the main repo is. This is
needed for when the --repository option is used.

Adds tests to test-bundle and a new test script
test-mq-pull-from-bundle, which plays out the situation that initially
made me detect this bug

(hg -R .hg/patches pull ../bundle.hg).

#!/bin/sh

hg init
echo a > a
hg ci -Am t

hg mv a b
hg ci -Am t1
hg debugrename b

hg mv b a
hg ci -Am t2
hg debugrename a

echo % test with --rev
hg debugrename --rev 1 b