BUG/MINOR: cfgparse: do not mention "addr:port" as supported on proxy lines

The very old error message indicating that a proxy name is mandatory
still had a reference to the optional addr:port argument while this one
is explicitly rejected a few lines later since at least 1.9.

This is harmless but confusing. This can be backported to 2.0.
diff --git a/src/cfgparse-listen.c b/src/cfgparse-listen.c
index 3c66e61..80b845a 100644
--- a/src/cfgparse-listen.c
+++ b/src/cfgparse-listen.c
@@ -189,8 +189,7 @@
 
 	if (rc != PR_CAP_NONE) {  /* new proxy */
 		if (!*args[1]) {
-			ha_alert("parsing [%s:%d] : '%s' expects an <id> argument and\n"
-				 "  optionally supports [addr1]:port1[-end1]{,[addr]:port[-end]}...\n",
+			ha_alert("parsing [%s:%d] : '%s' expects an <id> argument\n",
 				 file, linenum, args[0]);
 			err_code |= ERR_ALERT | ERR_ABORT;
 			goto out;