ui: provide official way to reset internal state per command
This will allow us to clear in-memory password storage per runcommand().
I've updated commandserver to call resetstate() of both ui and repo.ui because
they may have different states in theory.
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" | \
cat
}