[gnome-builder] html: fix segfault when completing "<!"

[Christian Hergert <chergert src gnome org>]

commit 6ed08c56d935bf69bb15817372e4ca8886949f76
Author: Christian Hergert <christian hergert me>
Date:   Sat Jan 10 23:41:07 2015 -0800

    html: fix segfault when completing "<!"

 src/html/gb-html-completion-provider.c |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)
---
diff --git a/src/html/gb-html-completion-provider.c b/src/html/gb-html-completion-provider.c
index 7c0476a..dc27177 100644
--- a/src/html/gb-html-completion-provider.c
+++ b/src/html/gb-html-completion-provider.c
@@ -381,9 +381,11 @@ gb_html_completion_provider_populate (GtkSourceCompletionProvider *provider,
       {
         gchar *element;
 
-        element = get_element (context);
-        trie = g_hash_table_lookup (element_attrs, element);
-        g_free (element);
+        if ((element = get_element (context)))
+          {
+            trie = g_hash_table_lookup (element_attrs, element);
+            g_free (element);
+          }
 
         break;
       }