Automatic update of common submodule

From c408583 to 21ba2e5

diff --git a/common b/common
index c4085835384c8a177072dd6b38bcc3669a529b0a..21ba2e575a0ecb8c51b46fa31d4b9cfd699da8b2 160000 (submodule)
--- a/common
+++ b/common
@@ -1 +1 @@
-Subproject commit c4085835384c8a177072dd6b38bcc3669a529b0a
+Subproject commit 21ba2e575a0ecb8c51b46fa31d4b9cfd699da8b2