genstrings not working correctly with OBALoc() format variant

[aaronbrethorst]

The variant of OBALoc that includes a format: parameter isn't being correctly interpreted by genstrings, which is invoked in the extract_strings script. It's not clear based on a cursory glance whether this is something that can be corrected with genstrings, or if we need to just remove this OBALoc variant and do things the hard way with it.

Repro:

1. Run script/extract_strings
2. Look at the diff for OBAKit/Strings/en.lproj/Localizable.strings — specifically, look at "data_migration_bulletin.report_summary_number_of_successes" and "data_migration_bulletin.report_summary_number_of_failures"

Expected:

These two keys have the values "%d successful" and "%d failures", respectively.

Actual:

They don't.

[aaronbrethorst]

fyi @ualch9