[shotwell] Remove obsolete external

[Jens Georg <jensgeorg src gnome org>]

commit c2a42623d3b720c3bdfc037709f2b33e142479fd
Author: Jens Georg <mail jensge org>
Date:   Sat Jul 8 09:10:26 2017 +0200

    Remove obsolete external
    
    collate_key_for_filename() is bound since ages now

 src/SortedList.vala            |    4 +---
 src/Thumbnail.vala             |    7 +++----
 src/folders/FoldersBranch.vala |    2 +-
 3 files changed, 5 insertions(+), 8 deletions(-)
---
diff --git a/src/SortedList.vala b/src/SortedList.vala
index 00672ab..727b523 100644
--- a/src/SortedList.vala
+++ b/src/SortedList.vala
@@ -6,8 +6,6 @@
 
 public delegate int64 Comparator(void *a, void *b);
 
-extern string g_utf8_collate_key_for_filename(string str, ssize_t len = -1);
-
 public int64 file_comparator(void *a, void *b) {
     string? path_a = ((File *) a)->get_path();
     string? path_b = ((File *) b)->get_path();
@@ -19,7 +17,7 @@ public int64 file_comparator(void *a, void *b) {
     if (path_b == null)
         return -1;
     
-    return strcmp(g_utf8_collate_key_for_filename(path_a), g_utf8_collate_key_for_filename(path_b));
+    return strcmp(path_a.collate_key_for_filename(), path_b.collate_key_for_filename());
 }
 
 public class SortedList<G> : Object, Gee.Traversable<G>, Gee.Iterable<G>, Gee.Collection<G> {
diff --git a/src/Thumbnail.vala b/src/Thumbnail.vala
index 2fe28e8..4ff4381 100644
--- a/src/Thumbnail.vala
+++ b/src/Thumbnail.vala
@@ -198,12 +198,11 @@ public class Thumbnail : MediaSourceItem {
     public static int64 filename_ascending_comparator(void *a, void *b) {
         string path_a = ((Thumbnail *) a)->media.get_file().get_basename().down();
         string path_b = ((Thumbnail *) b)->media.get_file().get_basename().down();
-        
-        int64 result = strcmp(g_utf8_collate_key_for_filename(path_a), 
-            g_utf8_collate_key_for_filename(path_b));
+
+        int64 result = strcmp(path_a.collate_key_for_filename(), path_b.collate_key_for_filename());
         return (result != 0) ? result : photo_id_ascending_comparator(a, b);
     }
-    
+
     public static int64 filename_descending_comparator(void *a, void *b) {
         int64 result = filename_ascending_comparator(b, a);
         
diff --git a/src/folders/FoldersBranch.vala b/src/folders/FoldersBranch.vala
index d14a148..272456c 100644
--- a/src/folders/FoldersBranch.vala
+++ b/src/folders/FoldersBranch.vala
@@ -168,7 +168,7 @@ public class Folders.SidebarEntry : Sidebar.SimplePageEntry, Sidebar.ExpandableE
     
     public SidebarEntry(File dir) {
         this.dir = dir;
-        collation = g_utf8_collate_key_for_filename(dir.get_path());
+        collation = dir.get_path().collate_key_for_filename();
     }
     
     public override string get_sidebar_name() {