Don't call putmsgptrs() from logout() unless the SS_USERON sys_status flag

is set: this insures that uninitialized msg-scan ptrs/cfg won't be
written to disk unless a successful logon()/getmsgptrs() was called first.
This probably fixes the sighting that echicken reported where a failed
SSH login caused his sub-scan config file (data/user/0001.subs) to contain
uninitialized/garbage values.
logout() could be called from multiple places (e.g. JS and Baja modules),
even before a successful login is completed, so this sighting is not
entirely impractical.

src/sbbs3/logout.cpp

@@ -108,7 +108,9 @@ void sbbs_t::logout()
 		remove(path);
 
 	delfiles(cfg.temp_dir,ALLFILES);
-	putmsgptrs();
+	if(sys_status&SS_USERON) {	// Insures the useron actually when through logon()/getmsgptrs() first
+		putmsgptrs();
+	}
 	if(!REALSYSOP)
 		logofflist();
 	useron.laston=(time32_t)now;