MINOR: cli: delare the CLI frontend as an internal proxy

Declare the CLI frontend as an internal proxy so we can check the
PR_CAP_INT flag instead of the global.fe_cli pointer for generic use
cases.
diff --git a/src/cli.c b/src/cli.c
index 3bc22cf..9d6354c 100644
--- a/src/cli.c
+++ b/src/cli.c
@@ -380,7 +380,7 @@
 	proxies_list = fe;
 	fe->last_change = now.tv_sec;
 	fe->id = strdup("GLOBAL");
-	fe->cap = PR_CAP_FE;
+	fe->cap = PR_CAP_FE|PR_CAP_INT;
 	fe->maxconn = 10;                 /* default to 10 concurrent connections */
 	fe->timeout.client = MS_TO_TICKS(10000); /* default timeout of 10 seconds */
 	fe->conf.file = strdup(file);