tests/test-1102

rebase: keep original mq patch format (Issue1574)

Rebase now doesn't make assumptions about which format has been
used for a mq patch (git or normal).
Before finalizing a patch it keeps track of the original format,
by reading its header, and then restores the format when reimporting
it.
This way it also allows for having mixed styles.

Note: this version corrects a failure in the test

#!/bin/sh

rm -rf a
hg init a
cd a
echo a > a
hg ci -Am0
hg tag t1 # 1
hg tag --remove t1 # 2

hg co 1
hg tag -r0 t1
hg tags