check-code: better check for overwriting $HGRCPATH
Suggested by Mads Kiilerich on IRC.
tests: don't overwrite HGRCPATH
Overwriting instead of appending to the file removes the [defaults]
section put into the file by run-tests.py.
It also defeats the --inotify option to run-tests.py.
(Nothing was broken yet, but the lack of -d "0 0" cause changeset
hashes to change unexpectedly in a test case I was editing.)
Added signature for changeset
2616325766e3