Define mgcp_rtp_end.output_enabled as bool

Change-Id: I55f7796ef774f86050041f2c5e3a2f8f7d1f56df
diff --git a/tests/mgcp/mgcp_test.c b/tests/mgcp/mgcp_test.c
index a8aad14..9b4933c 100644
--- a/tests/mgcp/mgcp_test.c
+++ b/tests/mgcp/mgcp_test.c
@@ -868,7 +868,7 @@
 					printf("Connection mode not set\n");
 
 				OSMO_ASSERT(conn->end.output_enabled
-					    == (conn->conn->mode & MGCP_CONN_SEND_ONLY ? 1 : 0));
+					    == !!(conn->conn->mode & MGCP_CONN_SEND_ONLY));
 
 				conn->conn->mode |= CONN_UNMODIFIED;