virchrdev: Don't leak mutex if virChrdevAlloc() fails

This is only a theoretical leak, but in virChrdevAlloc() we
initialize a mutex and if creating a hash table fails,
then virChrdevFree() is called which because of incorrect check
doesn't deinit the mutex.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>

src/conf/virchrdev.c

@@ -311,7 +311,7 @@ static int virChrdevFreeClearCallbacks(void *payload,
  */
 void virChrdevFree(virChrdevsPtr devs)
 {
-    if (!devs || !devs->hash)
+    if (!devs)
         return;
 
     virMutexLock(&devs->lock);