inotify: don't fall over just because of a dangling symlink
Previously, the inotify server failed to start if .hg/inotify.sock was
a symlink that pointed to a non-existent path. This behaviour does not
seem to make any sense.
Now, if we encounter a broken symlink, we unlink it and continue.
# When --inotify is activated, help output and config changes:
test-debugcomplete
test-empty
test-fncache
test-globalopts
test-help
test-hgrc
test-inherit-mode
test-qrecord
test-strict
# --inotify activates de facto the inotify extension. It does not play well
# with inotify-specific tests, which activate/deactivate inotify at will:
test-inotify
test-inotify-debuginotify
test-inotify-dirty-dirstate
test-inotify-issue1208
test-inotify-issue1371
test-inotify-issue1542
test-inotify-issue1556
test-inotify-lookup