[pangomm] Attribute: fix operator!=

[Murray Cumming <murrayc src gnome org>]

commit bfe080fe37e1a17726fd9b1c4cabbc117c91ac93
Author: Maks Naumov <maksqwe1 ukr net>
Date:   Fri Jun 26 13:11:55 2015 +0300

    Attribute: fix operator!=
    
    Bug #751531

 pango/src/attributes.hg |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/pango/src/attributes.hg b/pango/src/attributes.hg
index 00bc8d9..d07d71d 100644
--- a/pango/src/attributes.hg
+++ b/pango/src/attributes.hg
@@ -230,7 +230,7 @@ inline bool operator==(const Attribute& lhs, const Attribute& rhs)
 /** @relates Pango::Attribute */
 inline bool operator!=(const Attribute& lhs, const Attribute& rhs)
 {
-  return lhs.equal(rhs);
+  return !lhs.equal(rhs);
 }