Bump libgit2 to 1318ec9

vmg · vmg · commit 71bb9ab0e3f8 · 2015-11-02T14:28:40.000+01:00
diff --git a/vendor/libgit2 b/vendor/libgit2
@@ -1 +1 @@
-Subproject commit 232a7e3205ede0e16ee9f88962ba5020167d95f4
+Subproject commit 1318ec91a142d442718dc8430da4499b7739a088
