qemu: avoid deadlock on domain object enter monitor fail

Should be followed with qemuDomainObjExitMonitor only if
qemuDomainObjEnterMonitorAsync returns 0.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

src/qemu/qemu_migration.c

@@ -108,7 +108,7 @@ qemuMigrationCheckTLSCreds(virQEMUDriverPtr driver,
     qemuMonitorMigrationParams migParams = { 0 };
 
     if (qemuDomainObjEnterMonitorAsync(driver, vm, asyncJob) < 0)
-        goto cleanup;
+        return -1;
 
     if (qemuMonitorGetMigrationParams(priv->mon, &migParams) < 0)
         goto cleanup;

src/qemu/qemu_process.c

@@ -4349,7 +4349,7 @@ qemuProcessSetupBalloon(virQEMUDriverPtr driver,
         return 0;
 
     if (qemuDomainObjEnterMonitorAsync(driver, vm, asyncJob) < 0)
-        goto cleanup;
+        return -1;
 
     if (vm->def->memballoon->period)
         qemuMonitorSetMemoryStatsPeriod(priv->mon, vm->def->memballoon,