Bump libgit2 to 855f048

vmg · vmg · commit e097f1403be6 · 2015-10-21T14:42:40.000+02:00
diff --git a/vendor/libgit2 b/vendor/libgit2
@@ -1 +1 @@
-Subproject commit d5f7aad810b4232da433b94e3ecf658a75bd145c
+Subproject commit 855f048a7b28de8c1f44a570aee93a26cc684a60
