Bring back old cracky sounds

mods/default/README.txt

@@ -262,6 +262,8 @@ Glass breaking sounds (CC BY 3.0):
   3: http://www.freesound.org/people/lsprice/sounds/88808/
 
 Mito551 (sounds) (CC BY-SA 3.0):
+  default_dig_cracky.ogg
+  default_dug_cracky.*.ogg
   default_dig_crumbly.*.ogg
   default_dig_dig_immediate.ogg
   default_dig_oddly_breakable_by_hand.ogg

mods/default/functions.lua

@@ -18,7 +18,7 @@ function default.node_sound_stone_defaults(tbl)
 	tbl.footstep = tbl.footstep or
 			{name = "default_hard_footstep", gain = 0.2}
 	tbl.dug = tbl.dug or
-			{name = "default_hard_footstep", gain = 1.0}
+			{name = "default_dug_cracky", gain = 1.0}
 	default.node_sound_defaults(tbl)
 	return tbl
 end