MEDIUM: cli: enable "show cli sockets" for the master

Enable the keyword on the master CLI.
diff --git a/src/cli.c b/src/cli.c
index cc1f681..f4c5167 100644
--- a/src/cli.c
+++ b/src/cli.c
@@ -2327,7 +2327,7 @@
 	{ { "set", "severity-output",  NULL }, "set severity-output [none|number|string] : set presence of severity level in feedback information", cli_parse_set_severity_output, NULL, NULL },
 	{ { "set", "timeout",  NULL }, "set timeout    : change a timeout setting", cli_parse_set_timeout, NULL, NULL },
 	{ { "show", "env",  NULL }, "show env [var] : dump environment variables known to the process", cli_parse_show_env, cli_io_handler_show_env, NULL },
-	{ { "show", "cli", "sockets",  NULL }, "show cli sockets : dump list of cli sockets", cli_parse_default, cli_io_handler_show_cli_sock, NULL },
+	{ { "show", "cli", "sockets",  NULL }, "show cli sockets : dump list of cli sockets", cli_parse_default, cli_io_handler_show_cli_sock, NULL, NULL, ACCESS_MASTER },
 	{ { "show", "fd", NULL }, "show fd [num] : dump list of file descriptors in use", cli_parse_show_fd, cli_io_handler_show_fd, NULL },
 	{ { "show", "activity", NULL }, "show activity : show per-thread activity stats (for support/developers)", cli_parse_default, cli_io_handler_show_activity, NULL },
 	{ { "show", "proc", NULL }, "show proc      : show processes status", cli_parse_default, cli_io_handler_show_proc, NULL, NULL, ACCESS_MASTER_ONLY},