disallow http_server_body with flow:to_server

disallow http_server_body with flow:to_server or from_client

src/detect-http-server-body.c

@@ -122,7 +122,10 @@ int DetectHttpServerBodySetup(DetectEngineCtx *de_ctx, Signature *s, char *arg)
                    "be used with the rawbytes rule keyword");
         return -1;
     }
-
+    if (s->init_flags & SIG_FLAG_INIT_FLOW && s->flags & SIG_FLAG_TOSERVER && !(s->flags & SIG_FLAG_TOCLIENT)) {
+        SCLogError(SC_ERR_INVALID_SIGNATURE, "http_server_body cannot be used with flow:to_server or from_client");
+        return -1;
+    }
     if (s->alproto != ALPROTO_UNKNOWN && s->alproto != ALPROTO_HTTP) {
         SCLogError(SC_ERR_CONFLICTING_RULE_KEYWORDS, "rule contains a non http "
                    "alproto set");