Fix issue encountered when trying to reopen a file stored remotely

lib/carrierwave/processing/rmagick.rb

@@ -372,7 +372,7 @@ def destroy_image(image)
     end
 
     def rmagick_image
-      ::Magick::Image.read(current_path).first
+      ::Magick::Image.from_blob(self.read).first
     end
 
   end # RMagick

spec/processing/rmagick_spec.rb

@@ -220,6 +220,38 @@
     end
   end
 
+  describe "#rmagick_image", focus: true do
+    it "returns a ::Magick::Image" do
+      expect{instance.send(:rmagick_image)}.to_not raise_exception
+      expect(instance.send(:rmagick_image).class).to eq(::Magick::Image)
+    end
+
+    context "with a remotely stored file" do
+      class RemoteFile < CarrierWave::SanitizedFile
+        def initialize local_path
+          @local_path = local_path
+        end
+
+        def current_path
+          "foo/bar.jpg"
+        end
+
+        def read
+          File.read @local_path
+        end
+      end
+
+      before do
+        allow(instance).to receive(:file).and_return(RemoteFile.new(landscape_file_copy_path))
+      end
+
+      it "returns a ::Magick::Image" do
+        expect{instance.send(:rmagick_image)}.to_not raise_exception
+        expect(instance.send(:rmagick_image).class).to eq(::Magick::Image)
+      end
+    end
+  end
+
   describe "test errors" do
     context "invalid image file" do
       before do