ssh: unban the use of pipe character in user@host:port string
This vulnerability was fixed by the previous patch and there were more ways
to exploit than using '|shellcmd'. So it doesn't make sense to reject only
pipe character.
Test cases are updated to actually try to exploit the bug. As the SSH bridge
of git/svn subrepos are not managed by our code, the tests for non-hg subrepos
are just removed.
This may be folded into the original patches.
Our full contribution guidelines are in our wiki, please see:
https://www.mercurial-scm.org/wiki/ContributingChanges
If you just want a checklist to follow, you can go straight to
https://www.mercurial-scm.org/wiki/ContributingChanges#Submission_checklist
If you can't run the entire testsuite for some reason (it can be
difficult on Windows), please at least run `contrib/check-code.py` on
any files you've modified and run `python contrib/check-commit` on any
commits you've made (for example, `python contrib/check-commit
273ce12ad8f1` will report some style violations on a very old commit).