Actually build correct branch for mod_auth_gssapi

diff --git a/mod_auth_gssapi b/mod_auth_gssapi
index 7f6117b..c2ee581 160000 (submodule)
--- a/mod_auth_gssapi
+++ b/mod_auth_gssapi
@@ -1 +1 @@
-Subproject commit 7f6117b6c7f69e405aa1f2171af2de846024d296
+Subproject commit c2ee5818408bc81ea071cef1a5b7cf79298a69b1