* Use "HEAD" instead of "FETCH_HEAD" for patch branch.
FETCH_HEAD might change, if another fetch is done. HEAD
always points to the currently checked out commit, that
has been built.
* Add --patch-config to use the same config as for the baseline
(see .travis/regression-tester.sh). However, currently this
is ignored, when "--auto-gen-config" is used.
* Use long argument names for better readability
Fixes#2820
