[glib] GObject: fixup reversed logic in last commit

[Ryan Lortie <ryanl src gnome org>]

commit 958f2bac7a123bc0cf35c5afab6ac62c80b0c03b
Author: Ryan Lortie <desrt desrt ca>
Date:   Tue Dec 20 15:29:16 2011 -0500

    GObject: fixup reversed logic in last commit
    
    Accidentally dropped a !.

 gobject/gobject.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gobject/gobject.c b/gobject/gobject.c
index c581839..eabd2fe 100644
--- a/gobject/gobject.c
+++ b/gobject/gobject.c
@@ -1380,7 +1380,7 @@ object_interface_check_properties (gpointer func_data,
        * the READABLE and WRITABLE flags. We also simplify here
        * by only checking the value type, not the G_PARAM_SPEC_TYPE.
        */
-      if (g_type_is_a (pspecs[n]->value_type, class_pspec->value_type))
+      if (!g_type_is_a (pspecs[n]->value_type, class_pspec->value_type))
         g_critical ("Property '%s' on class '%s' has type '%s' "
                     "which is different from the type '%s', "
                     "of the property on interface '%s'\n",