Add placeholders for missing repack_locales switches

On some embedded setups and Windows unittest targets bring in
new locale repack actions which use the -g and -b switches of
repack_locals.py with @pymod_do_main. Since we did not implement
these options the script execution failed. Add placeholders for
these options.

Change-Id: Ie11928b025448bc059fb1e3f2e695fb7698a7937
Reviewed-by: Michael Bruning <michael.bruning@digia.com>
Reviewed-by: Zoltan Arvai <zarvai@inf.u-szeged.hu>
Reviewed-by: Pierre Rossi <pierre.rossi@gmail.com>