auto-upgrade: add a test case where the repository is already locked
This show the current behavior when the repository to auto-upgrade is already
locked.
The current behavior is to abort, which is probably not great. Now that we have
a proper test, we can think about the behavior we wants in a later tests.
Differential Revision: https://phab.mercurial-scm.org/D12618
edition = "2018"
max_width = 79
wrap_comments = true
error_on_line_overflow = true