tests: Set up two more overrides for root builders

There are two more places after commit 3865941b that need to be adapted
in order to get rid of some test failures when building as root.
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

tests/networkxml2firewalltest.c

@@ -135,6 +135,8 @@ mymain(void)
             ret = -1;                                                   \
     } while (0)
 
+    virFirewallSetLockOverride(true);
+
     if (virFirewallSetBackend(VIR_FIREWALL_BACKEND_DIRECT) < 0) {
         ret = -1;
         goto cleanup;

tests/virfirewalltest.c

@@ -1168,6 +1168,8 @@ mymain(void)
     RUN_TEST_DIRECT(name, method)
 # endif /* ! WITH_DBUS */
 
+    virFirewallSetLockOverride(true);
+
     RUN_TEST("single group", testFirewallSingleGroup);
     RUN_TEST("remove rule", testFirewallRemoveRule);
     RUN_TEST("many groups", testFirewallManyGroups);