Ecore: Fix invalid lock count if DEBUG is enabled

With -DDEBUG, we can see an error message, like:
ERR: You are calling _ecore_lock() from outside of the main loop
     threads in lib/ecore/ecore_private at line 306

Looking at the code shows that ecore_lock fails immediately if
thread debugging is enabled, but ecore_unlock does not, so the
value _ecore_main_lock_count could go below 0.

This is not very important as the value is never used.

src/lib/ecore/ecore_private.h

@@ -312,6 +312,10 @@ _ecore_lock(void)
 static inline void
 _ecore_unlock(void)
 {
+#ifndef HAVE_THREAD_SAFETY
+   /* see _ecore_lock(); no-op unless EINA_HAVE_DEBUG_THREADS is defined */
+   EINA_MAIN_LOOP_CHECK_RETURN;
+#endif
    _ecore_main_lock_count--;
    /* assert(_ecore_main_lock_count == 0); */
 #ifdef HAVE_THREAD_SAFETY