Revert "Don't allow calling Kernel methods via loader/saver options"

It doesn't fully resolve the security vulnerability, and there is no
point in only partially resolving it.

See #100

This reverts commit aed5b80.

CHANGELOG.md

@@ -1,7 +1,5 @@
 ## HEAD
 
-* [minimagick] Don't allow calling Kernel options via `loader`/`saver` options (@janko)
-
 * Add `#cover` that allows one to resize an image to cover a given width and height without cropping
   the excess. (@brendon)
 

lib/image_processing/mini_magick.rb

@@ -223,9 +223,9 @@ def disallow_split_layers!(destination_path)
         def apply_options(magick, define: {}, **options)
           options.each do |option, value|
             case value
-            when true, nil then magick.public_send(option)
-            when false     then magick.public_send(option).+
-            else                magick.public_send(option, *value)
+            when true, nil then magick.send(option)
+            when false     then magick.send(option).+
+            else                magick.send(option, *value)
             end
           end
 

test/mini_magick_test.rb

@@ -174,26 +174,6 @@
     assert_dimensions [600, 800], result
   end
 
-  it "doesn't allow calling Kernel methods via loader/saver options" do
-    error = assert_raises(MiniMagick::Error) do
-      ImageProcessing::MiniMagick
-        .source(@portrait)
-        .loader(system: "touch test/malicious.txt")
-        .call
-    end
-
-    assert_match "unrecognized option `-system'", error.message
-
-    error = assert_raises(MiniMagick::Error) do
-      ImageProcessing::MiniMagick
-        .source(@portrait)
-        .saver(system: "touch test/malicious.txt")
-        .call
-    end
-
-    assert_match "unrecognized option `-system'", error.message
-  end
-
   describe ".valid_image?" do
     it "returns true for correct images" do
       assert ImageProcessing::MiniMagick.valid_image?(@portrait)