Stop classifying msgs for unknown areas as security violations

When Secure EchoMail is enabled and a Bad Echo Area (*) is defined in the
area file (areas.bbs), but the packet source address is *not* listed as a
link to the Bad Echo Area (tag: *) in areas.bbs, any messages for unknown
areas in such a packet would cause the pkt to be considered a bad packet
with a security violation. Instead, the message should just be skipped.

src/sbbs3/sbbsecho.c

@@ -5884,7 +5884,7 @@ void import_packets(const char* inbound, nodecfg_t* inbox, bool secure)
 					lprintf(LOG_NOTICE, "Adding unknown area (%s) to bad area list: %s", areatag, cfg.badareafile);
 					strListPush(&bad_areas, areatag);
 				}
-				if(cfg.badecho>=0) {
+				if(cfg.badecho>=0 && (cfg.secure_echomail == false || area_is_linked(cfg.badecho, &pkt_orig))) {
 					i=cfg.badecho;
 					if(cfg.area[i].sub!=INVALID_SUB)
 						printf("%s ",scfg.sub[cfg.area[i].sub]->code);