update libgit2 to support streaming filters

ammeep · ammeep · commit 17dd29ed6d28 · 2015-02-26T16:41:00.000-08:00
diff --git a/libgit2 b/libgit2
@@ -1 +1 @@
-Subproject commit e0902fbce7d14631bd02091c1c70cde3e68f78ab
+Subproject commit d15884ce840c7eeac54fc408fdc33e03cd01bc32
