qemu_conf: Properly check for retval of qemuDomainNamespaceAvailable

This function is returning a boolean therefore check for '< 0'
makes no sense. It should have been
'!qemuDomainNamespaceAvailable'.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>

src/qemu/qemu_conf.c

@@ -837,7 +837,7 @@ int virQEMUDriverConfigLoadFile(virQEMUDriverConfigPtr cfg,
                 goto cleanup;
             }
 
-            if (qemuDomainNamespaceAvailable(ns) < 0) {
+            if (!qemuDomainNamespaceAvailable(ns)) {
                 virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
                                _("%s namespace is not available"),
                                namespaces[i]);