[BUG] http: the transaction must be initialized even in TCP mode

When running in pure TCP mode with a traffic inspection rule to detect
HTTP protocol, we have to initialize the HTTP transaction too. The
effect of not doing this was that some incoming connections could have
been matched as carrying HTTP protocol eventhough this was not the case.
diff --git a/src/client.c b/src/client.c
index 2955de0..444d47f 100644
--- a/src/client.c
+++ b/src/client.c
@@ -301,10 +301,10 @@
 
 			if ((txn->hdr_idx.v = pool_alloc2(p->hdr_idx_pool)) == NULL)
 				goto out_fail_idx; /* no memory */
-		}
 
-		if (p->mode == PR_MODE_HTTP)
+			/* and now initialize the HTTP transaction state */
 			http_init_txn(s);
+		}
 
 		if ((p->mode == PR_MODE_TCP || p->mode == PR_MODE_HTTP)
 		    && (p->logfac1 >= 0 || p->logfac2 >= 0)) {