Attempt to re-create outbound directories in mutex (.bsy) file lock loop, just

in case something (e.g. Argus mailer) deleted it while we were waiting our
turn to use it. As reported by Alterego (ALTERANT)

src/sbbs3/sbbsecho.c

@@ -776,6 +776,7 @@ bool bso_lock_node(fidoaddr_t dest)
 		if(terminated)
 			return false;
 		SLEEP(cfg.bso_lock_delay*1000);
+		mkpath(outbound); // Just in case something (e.g. Argus) deleted the outbound directory
 	}
 	strListPush(&locked_bso_nodes, fname);
 	lprintf(LOG_DEBUG, "Node (%s) successfully locked via: %s", smb_faddrtoa(&dest, NULL), fname);