EAP-FAST peer: Fix PAC parser error messages

Do not override the parsing error with the "PAC block not terminated
with END" message if the reason for the END line not yet being seen is
in failure to parse an earlier line.

Signed-off-by: Jouni Malinen <j@w1.fi>

src/eap_peer/eap_fast_pac.c

@@ -455,7 +455,8 @@ int eap_fast_load_pac(struct eap_sm *sm, struct eap_fast_pac **pac_root,
 	}
 
 	if (pac) {
-		err = "PAC block not terminated with END";
+		if (!err)
+			err = "PAC block not terminated with END";
 		eap_fast_free_pac(pac);
 	}