Merge pull request #1982 from RosettaCommons/roccomoretti/ubsan_fixes
Fix two issues which were causing errors with the undefined behavior checker.
In LoopProtocol, explicitly cast the regex match to a string, rather than whatever odd type it is under the hood.
In MotifGraftMover, explicitly initialize variables in a plain-data struct, as the uninitialized values were causing issues when the structures were copied. ("2" is not a bool.)