mq: don't allow patches with some reserved names
The current list of reserved names includes only mq control files.
Also, reserve names starting with ".hg" (to avoid troubles with
e.g. .hgignore and .hgtags), and with ".mq" (to allow future
extensions).
This should fix
issue841.
mq: pop/refresh: avoid losing revisions not managed by mq
We already disallow committing on top of an mq revision exactly
to avoid losing this new revision during a qpop/qrefresh, so this
can be seen as an additional safety check.
If this is not enough to fix
issue844, it should at least prevent
it from happening.