FIX: don't restrict to local filesystem for df check

FIX: check correct directory when looking at backup limits

app/controllers/admin/backups_controller.rb

@@ -137,7 +137,7 @@ class Admin::BackupsController < Admin::AdminController
   private
 
   def has_enough_space_on_disk?(size)
-    `df -Pk . | awk 'NR==2 {print $4 * 1024;}'`.to_i > size
+    `df -Pk #{Rails.root}/public/backups | awk 'NR==2 {print $4 * 1024;}'`.to_i > size
   end
 
 end

lib/cooked_post_processor.rb

@@ -264,7 +264,7 @@ class CookedPostProcessor
   end
 
   def available_disk_space
-    100 - `df -l #{Rails.root}/public/uploads | tail -1 | tr -s ' ' | cut -d ' ' -f 5`.to_i
+    100 - `df -P #{Rails.root}/public/uploads | tail -1 | tr -s ' ' | cut -d ' ' -f 5`.to_i
   end
 
   def dirty?