libobjc: Fix obvious typo in comment

[Nicola Pero]

Fixes a typo in a comment in my last patch.  Applied to trunk.

Thanks

Index: ChangeLog
===================================================================
--- ChangeLog	(revision 177505)
+++ ChangeLog	(working copy)
@@ -1,5 +1,9 @@
 2011-08-06  Nicola Pero  <nicola.pero@meta-innovation.com>
 
+	* class.c (class_getSuperclass): Fixed typo in comment.
+	
+2011-08-06  Nicola Pero  <nicola.pero@meta-innovation.com>
+
 	PR libobjc/49882
 	* class.c (class_getSuperclass): Return the superclass if the
 	class is in construction.
Index: class.c
===================================================================
--- class.c	(revision 177505)
+++ class.c	(working copy)
@@ -925,7 +925,7 @@
 
   /* Classes that are in construction are not resolved, and still have
      the class name (instead of a class pointer) in the
-     class_->superclass field.  In that case we need to lookup the
+     class_->super_class field.  In that case we need to lookup the
      superclass name to return the superclass.  We can not resolve the
      class until it is registered.  */
   if (CLS_IS_IN_CONSTRUCTION (class_))