BUILD: shctx: do not depend on openssl anymore

The build breaks on a machine without openssl/crypto.h because shctx
still loads openssl-compat.h while it doesn't need it anymore since
the code was moved :

In file included from src/shctx.c:20:0:
include/proto/openssl-compat.h:3:28: fatal error: openssl/crypto.h: No such file or directory
 #include <openssl/crypto.h>

Just remove include openssl-compat from shctx.
diff --git a/src/shctx.c b/src/shctx.c
index 61fd12d..59ac8b8 100644
--- a/src/shctx.c
+++ b/src/shctx.c
@@ -17,7 +17,6 @@
 #include <types/global.h>
 #include <common/mini-clist.h>
 #include "proto/shctx.h"
-#include <proto/openssl-compat.h>
 
 #if !defined (USE_PRIVATE_CACHE)