Add a trailing slash to a modname arg that has no path information.

This ensures that the user gets a "skipping" message if they didn't
specify -r or -d.  (A trailing-slash was already being added to a
lone modname for --list-only transfers.)

clientserver.c

@@ -245,7 +245,7 @@ int start_inband_exchange(int f_in, int f_out, const char *user, int argc, char
 			rprintf(FERROR, "internal: args[] overflowed in do_cmd()\n");
 			exit_cleanup(RERR_SYNTAX);
 		}
-		if (list_only && strncmp(*argv, modname, modlen) == 0
+		if (strncmp(*argv, modname, modlen) == 0
 		 && argv[0][modlen] == '\0')
 			sargs[sargc++] = modname; /* we send "modname/" */
 		else