chgserver: add merge-tools to sensitive config items
Because this can change whether the ui is gui or not.
This fixes test-extdiff.t with chg.
run-tests: add --chg-debug flag to show chg debug output
This has helped me a lot in debugging chg failures in tests.
tests: update test-ssh.t output with --chg
The output change was caused by
d7304434390f5efca405744fa12a6585edae3d83.