[shotwell] Remove deprecated call from util/image.vala

[Jens Georg <jensgeorg src gnome org>]

commit cbb516968f97762cc3e80cc47a7a4904e8062772
Author: Jens Georg <mail jensge org>
Date:   Sat Oct 1 16:11:55 2016 +0200

    Remove deprecated call from util/image.vala
    
    Signed-off-by: Jens Georg <mail jensge org>

 src/util/image.vala |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/src/util/image.vala b/src/util/image.vala
index 92e276a..db872df 100644
--- a/src/util/image.vala
+++ b/src/util/image.vala
@@ -115,8 +115,8 @@ private const string fallback_image_missing[] = {
 };
 
 bool is_color_parsable(string spec) {
-    Gdk.Color color;
-    return Gdk.Color.parse(spec, out color);
+    var color = Gdk.RGBA ();
+    return color.parse(spec);
 }
 
 Gdk.RGBA parse_color(string spec) {