Fix core version.

Signed-off-by: Florent Bruneau <florent.bruneau@polytechnique.org>

diff --git a/core b/core
index e94c4a1..adc69ce 160000 (submodule)
--- a/core
+++ b/core
@@ -1 +1 @@
-Subproject commit e94c4a1713cc0d63508a5d0ecd2d572f047975fb
+Subproject commit adc69ced9c75421c5ee596fbd0a3426fffb9940c