Bump ORCA to 1.681.

gpAux/releng/releng.mk

@@ -172,7 +172,7 @@ sync_tools: opt_write_test /opt/releng/apache-ant
 	@echo "Resolve finished";
 
 	wget -O - https://github.com/greenplum-db/gpos/releases/download/v1.145/bin_gpos_centos5_release.tar.gz | tar zxf - -C $(BLD_TOP)/ext/$(BLD_ARCH)
-	wget -O - https://github.com/greenplum-db/gporca/releases/download/v1.678/bin_orca_centos5_release.tar.gz | tar zxf - -C $(BLD_TOP)/ext/$(BLD_ARCH)
+	wget -O - https://github.com/greenplum-db/gporca/releases/download/v1.681/bin_orca_centos5_release.tar.gz | tar zxf - -C $(BLD_TOP)/ext/$(BLD_ARCH)
 
 clean_tools: opt_write_test
 	@cd releng/make/dependencies; \