net/http: fix broken TestIssue4191_InfiniteGetToPutTimeout

Test creates 2 tcp connections for put and get. Make sure
these are closed properly after test is over, otherwise
server hangs waiting for connection to be closed.

R=golang-dev, bradfitz, dave
CC=golang-dev
https://golang.org/cl/6842109

src/pkg/net/http/transport_test.go

@@ -996,9 +996,11 @@ func TestIssue4191_InfiniteGetToPutTimeout(t *testing.T) {
 		req, _ := NewRequest("PUT", ts.URL+"/put", sres.Body)
 		_, err = client.Do(req)
 		if err == nil {
+			sres.Body.Close()
 			t.Errorf("Unexpected successful PUT")
 			break
 		}
+		sres.Body.Close()
 	}
 	if debug {
 		println("tests complete; waiting for handlers to finish")