qemu: don't lose error on setting monitor capabilities

Spotted by clang.  Regression introduced in commit e72cc3c1.

* src/qemu/qemu_driver.c (qemuConnectMonitor): Don't lose error status.

src/qemu/qemu_driver.c

@@ -1416,7 +1416,6 @@ qemuConnectMonitor(struct qemud_driver *driver, virDomainObjPtr vm)
     ret = qemuMonitorSetCapabilities(priv->mon);
     qemuDomainObjExitMonitorWithDriver(driver, vm);
 
-    ret = 0;
 error:
     if (ret < 0)
         qemuMonitorClose(priv->mon);