fix: don't try to copy .prf files in savegame-transfer

Since crawl/crawl@b7f16da2700d, these files
are not stored in the save directory any more, so for these versions,
mv -n gives an error. (However, savegame-transfer does appear to be
working despite the error. And mysteriously, some games still do have a
.prf present, but his may be an artifact of prior savegame transfers.)

This commit does *not* provide any cleanup for these files, so I
recommend that an admin manually clean them up. It may be easiest to
first do a savegame-transfer so they are collected in one place.

chroot/sbin/savegame-transfer.sh

@@ -83,7 +83,7 @@ do
 
                 if test -d ${PREFIX}/${BINARY_MAIN_NAME}-${POSSIBLE_GAME_HASH}/saves/${GAME_MODE}
                 then
-                    mv -n ${PREFIX}/${BINARY_MAIN_NAME}-${OUR_GAME_HASH}/saves/${GAME_MODE}/${CHAR_NAME}* ${PREFIX}/${BINARY_MAIN_NAME}-${OUR_GAME_HASH}/saves/${GAME_MODE}/start-${CHAR_NAME}-ns.prf ${PREFIX}/${BINARY_MAIN_NAME}-${POSSIBLE_GAME_HASH}/saves/${GAME_MODE}/
+                    mv -n ${PREFIX}/${BINARY_MAIN_NAME}-${OUR_GAME_HASH}/saves/${GAME_MODE}/${CHAR_NAME}* ${PREFIX}/${BINARY_MAIN_NAME}-${POSSIBLE_GAME_HASH}/saves/${GAME_MODE}/
                     if test $? -eq 0
                     then
                         echo -e " ${C_GREEN}successful.${C_NORMAL}"