Minor keyframe selection cleanups
Minor keyframe selection cleanups

Reviewers: sergey

Reviewed By: sergey

Differential Revision: https://developer.blender.org/D757

petertsoi/libmv,rgkoo/libmv-blender,rgkoo/libmv-blender,petertsoi/libmv,rgkoo/libmv-blender,petertsoi/libmv,SoylentGraham/libmv,rgkoo/libmv-blender,SoylentGraham/libmv,petertsoi/libmv,SoylentGraham/libmv,SoylentGraham/libmv,rgkoo/libmv-blender