sanlock: Avoid freeing uninitialized value

https://bugzilla.redhat.com/show_bug.cgi?id=1136788Signed-off-by: NJiri Denemark <jdenemar@redhat.com>

src/locking/lock_driver_sanlock.c

@@ -885,7 +885,7 @@ static int virLockManagerSanlockAcquire(virLockManagerPtr lock,
                                         int *fd)
 {
     virLockManagerSanlockPrivatePtr priv = lock->privateData;
-    struct sanlk_options *opt;
+    struct sanlk_options *opt = NULL;
     struct sanlk_resource **res_args;
     int res_count;
     bool res_free = false;