Fix format string handling in network driver

The call to virReportError conditionally switched between
two format strings, with different numbers of placeholders.
This meant the format string with no placeholders was not
protected by a "%s".
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

src/network/bridge_driver.c

@@ -1598,11 +1598,13 @@ networkAddMasqueradingIptablesRules(struct network_driver *driver,
                                      &network->def->forward.addr,
                                      &network->def->forward.port,
                                      NULL) < 0) {
-        virReportError(VIR_ERR_SYSTEM_ERROR,
-                       forwardIf ?
-                       _("failed to add iptables rule to enable masquerading to %s") :
-                       _("failed to add iptables rule to enable masquerading"),
-                       forwardIf);
+        if (forwardIf)
+            virReportError(VIR_ERR_SYSTEM_ERROR,
+                           _("failed to add iptables rule to enable masquerading to %s"),
+                           forwardIf);
+        else
+            virReportError(VIR_ERR_SYSTEM_ERROR, "%s",
+                           _("failed to add iptables rule to enable masquerading"));
         goto masqerr3;
     }
 
@@ -1614,11 +1616,13 @@ networkAddMasqueradingIptablesRules(struct network_driver *driver,
                                      &network->def->forward.addr,
                                      &network->def->forward.port,
                                      "udp") < 0) {
-        virReportError(VIR_ERR_SYSTEM_ERROR,
-                       forwardIf ?
-                       _("failed to add iptables rule to enable UDP masquerading to %s") :
-                       _("failed to add iptables rule to enable UDP masquerading"),
-                       forwardIf);
+        if (forwardIf)
+            virReportError(VIR_ERR_SYSTEM_ERROR,
+                           _("failed to add iptables rule to enable UDP masquerading to %s"),
+                           forwardIf);
+        else
+            virReportError(VIR_ERR_SYSTEM_ERROR, "%s",
+                           _("failed to add iptables rule to enable UDP masquerading"));
         goto masqerr4;
     }
 
@@ -1630,11 +1634,13 @@ networkAddMasqueradingIptablesRules(struct network_driver *driver,
                                      &network->def->forward.addr,
                                      &network->def->forward.port,
                                      "tcp") < 0) {
-        virReportError(VIR_ERR_SYSTEM_ERROR,
-                       forwardIf ?
-                       _("failed to add iptables rule to enable TCP masquerading to %s") :
-                       _("failed to add iptables rule to enable TCP masquerading"),
-                       forwardIf);
+        if (forwardIf)
+            virReportError(VIR_ERR_SYSTEM_ERROR,
+                           _("failed to add iptables rule to enable TCP masquerading to %s"),
+                           forwardIf);
+        else
+            virReportError(VIR_ERR_SYSTEM_ERROR, "%s",
+                           _("failed to add iptables rule to enable TCP masquerading"));
         goto masqerr5;
     }