MINOR: cli: set the ACCESS_MASTER* bits on the master bind_conf

Right now the code is a bit hackish, it tests for the keyword's level
flags but checks the applet's origin to compare the bits. Let's start
by properly setting the ACCESS_MASTER_ONLY and ACCESS_MASTER flags on
the master CLI's bind_conf so that they are automatically present
all the time.
diff --git a/src/cli.c b/src/cli.c
index 99cb9df..b21f1c5 100644
--- a/src/cli.c
+++ b/src/cli.c
@@ -2645,6 +2645,7 @@
 
 	bind_conf->level &= ~ACCESS_LVL_MASK;
 	bind_conf->level |= ACCESS_LVL_ADMIN;
+	bind_conf->level |= ACCESS_MASTER | ACCESS_MASTER_ONLY;
 
 	if (!str2listener(args[0], mworker_proxy, bind_conf, "master-socket", 0, &err)) {
 		ha_alert("Cannot create the listener of the master CLI\n");