Drop @grpc_java from labels
Drop @grpc_java from labels

These don't contribute if grpc-java is imported with name = grpc_java,
and break the build if grpc-java is imported with another name.
elandau/grpc-java,elandau/grpc-java,elandau/grpc-java,carl-mastrangelo/grpc-java,dapengzhang0/grpc-java,zhangkun83/grpc-java,ejona86/grpc-java,zhangkun83/grpc-java,carl-mastrangelo/grpc-java,grpc/grpc-java,carl-mastrangelo/grpc-java,zhangkun83/grpc-java,ejona86/grpc-java,zhangkun83/grpc-java,stanley-cheung/grpc-java,stanley-cheung/grpc-java,grpc/grpc-java,elandau/grpc-java,stanley-cheung/grpc-java,grpc/grpc-java,grpc/grpc-java,ejona86/grpc-java,dapengzhang0/grpc-java,dapengzhang0/grpc-java,carl-mastrangelo/grpc-java,dapengzhang0/grpc-java,stanley-cheung/grpc-java,ejona86/grpc-java