maint: change "" in err ? err->message : "" to _("unknown error"), ...

These changes avoid false-positive syntax-check failure,
and also make the resulting diagnostics more comprehensible.

src/qemu/qemu_driver.c

@@ -634,7 +634,7 @@ qemuAutostartDomain(void *payload, const char *name ATTRIBUTE_UNUSED, void *opaq
             virErrorPtr err = virGetLastError();
             VIR_ERROR(_("Failed to autostart VM '%s': %s"),
                       vm->def->name,
-                      err ? err->message : "");
+                      err ? err->message : _("unknown error"));
         } else {
             virDomainEventPtr event =
                 virDomainEventNewFromObj(vm,
@@ -2895,7 +2895,7 @@ qemudReattachManagedDevice(pciDevice *dev)
         if (pciReAttachDevice(dev) < 0) {
             virErrorPtr err = virGetLastError();
             VIR_ERROR(_("Failed to re-attach PCI device: %s"),
-                      err ? err->message : "");
+                      err ? err->message : _("unknown error"));
             virResetError(err);
         }
     }
@@ -2914,7 +2914,7 @@ qemuDomainReAttachHostDevices(struct qemud_driver *driver,
     if (!(pcidevs = qemuGetPciHostDeviceList(def))) {
         virErrorPtr err = virGetLastError();
         VIR_ERROR(_("Failed to allocate pciDeviceList: %s"),
-                  err ? err->message : "");
+                  err ? err->message : _("unknown error"));
         virResetError(err);
         return;
     }
@@ -2932,7 +2932,7 @@ qemuDomainReAttachHostDevices(struct qemud_driver *driver,
         if (pciResetDevice(dev, driver->activePciHostdevs) < 0) {
             virErrorPtr err = virGetLastError();
             VIR_ERROR(_("Failed to reset PCI device: %s"),
-                      err ? err->message : "");
+                      err ? err->message : _("unknown error"));
             virResetError(err);
         }
     }

src/secret/secret_driver.c

 /*
  * secret_driver.c: local driver for secret manipulation API
  *
- * Copyright (C) 2009 Red Hat, Inc.
+ * Copyright (C) 2009-2010 Red Hat, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -499,7 +499,7 @@ loadSecrets(virSecretDriverStatePtr driver,
             virErrorPtr err = virGetLastError();
 
             VIR_ERROR(_("Error reading secret: %s"),
-                      err != NULL ? err->message: "");
+                      err != NULL ? err->message: _("unknown error"));
             virResetError(err);
             continue;
         }

src/uml/uml_driver.c

@@ -157,7 +157,7 @@ umlAutostartDomain(void *payload, const char *name ATTRIBUTE_UNUSED, void *opaqu
         if (umlStartVMDaemon(data->conn, data->driver, vm) < 0) {
             virErrorPtr err = virGetLastError();
             VIR_ERROR(_("Failed to autostart VM '%s': %s"),
-                      vm->def->name, err ? err->message : "");
+                      vm->def->name, err ? err->message : _("unknown error"));
         }
     }
     virDomainObjUnlock(vm);