tags: do not abort if failed to write lock file to save cache
LockHeld wasn't enough to suppress error during acquiring lock. If .hg directory
is read-only, LockUnavailable will be raised.
$ chmod ugo-w .hg
$ hg identify
abort: could not lock working directory of ...: Permission denied
fixbundle() {
grep -v 'saving bundle' | grep -v 'saved backup' | \
grep -v added | grep -v adding | \
grep -v "unable to find 'e' for patching" | \
grep -v "e: No such file or directory"
}