[rygel/rygel-0-28] core: Fix small memory leak with XPath use

[Jens Georg <jensgeorg src gnome org>]

commit e33c5d7f4b0bba677d2c5a8b0287d2d257ab9e3d
Author: Jens Georg <mail jensge org>
Date:   Tue Feb 9 20:33:34 2016 +0100

    core: Fix small memory leak with XPath use
    
    Signed-off-by: Jens Georg <mail jensge org>

 src/librygel-core/rygel-description-file.vala |    8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)
---
diff --git a/src/librygel-core/rygel-description-file.vala b/src/librygel-core/rygel-description-file.vala
index e837dce..3190e8e 100644
--- a/src/librygel-core/rygel-description-file.vala
+++ b/src/librygel-core/rygel-description-file.vala
@@ -385,8 +385,12 @@ public class Rygel.DescriptionFile : Object {
         var retval = result != null &&
                      result->type == XPath.ObjectType.NODESET &&
                      !result->nodesetval->is_empty ();
-
-        xpo = result;
+        if (!retval && result != null) {
+            xpo = null;
+            delete result;
+        } else {
+            xpo = result;
+        }
 
         return retval;
     }