Error Trace:	/tmp/TestUpdate3127528187/001/etcd_test.go:113
        	Error:      	Received unexpected error:
        	            	key binlogupdate/updatekey in etcd not found
        	            	github.com/pingcap/errors.NotFoundf
        	            		external/com_github_pingcap_errors/juju_adaptor.go:117
        	            	github.com/pingcap/tidb/util/etcd.(*Client).Update
        	            		util/etcd/etcd.go:172
        	            	github.com/pingcap/tidb/util/etcd.TestUpdate
        	            		util/etcd/etcd_test.go:112
        	            	testing.tRunner
        	            		GOROOT/src/testing/testing.go:1446
        	            	runtime.goexit
        	            		GOROOT/src/runtime/asm_amd64.s:1594
        	Test:       	TestUpdate