Set error code ERROR_DDE_FAIL if the DDE connection failed in

ShellExecute().

dlls/shell32/shlexec.c

@@ -540,8 +540,9 @@ static unsigned dde_connect(WCHAR* key, WCHAR* start, WCHAR* ddeexec,
         if (!hConv)
         {
             TRACE("Couldn't connect. ret=%d\n", ret);
-            ret = 30; /* whatever */
-            goto error;
+            DdeUninitialize(ddeInst);
+            SetLastError(ERROR_DDE_FAIL);
+            return 30; /* whatever */
         }
         strcpyW(endkey, wIfexec);
         ifexeclen = sizeof(ifexec)/sizeof(WCHAR);