operation_tests.cpp:  Fix black_swan_issue_346 test
operation_tests.cpp:  Fix black_swan_issue_346 test

bitsuperlab/cpp-play2,bitsuperlab/cpp-play2,bigoc/openchain,pmconrad/graphene,abitmore/bitshares-2,peertracksinc/muse,pmconrad/graphene,peertracksinc/muse,abitmore/bitshares-2,bitsuperlab/cpp-play2,abitmore/bitshares-2,oxarbitrage/bitshares-core,oxarbitrage/bitshares-core,peertracksinc/muse,abitmore/bitshares-2,cryptonomex/graphene,oxarbitrage/bitshares-core,peertracksinc/muse,bitshares/bitshares-2,pmconrad/graphene,cryptonomex/graphene,bitshares/bitshares-2,cryptonomex/graphene,bitshares/bitshares-2,pmconrad/graphene,oxarbitrage/bitshares-core,bigoc/openchain,bigoc/openchain,bitshares/bitshares-2,bigoc/openchain