[MIGRATIONS] make orphaned com_cart migration more robust
[MIGRATIONS] make orphaned com_cart migration more robust

zweidner/hubzero-cms,anthonyfuentes/hubzero-cms,zooley/hubzero-cms,anthonyfuentes/hubzero-cms,zooley/hubzero-cms,anthonyfuentes/hubzero-cms,zweidner/hubzero-cms,anthonyfuentes/hubzero-cms,zooley/hubzero-cms,zweidner/hubzero-cms,zooley/hubzero-cms,zweidner/hubzero-cms