Fix typos and remove extra test

Author: victormier

lib/grim/image_magick_processor.rb

@@ -33,15 +33,15 @@ def save(pdf, index, path, options)
       command << width.to_s
       command << alpha if alpha
       command << "-antialias"
-      command << "-render",
+      command << "-render"
       command << "-quality"
       command << quality.to_s
       command << "-colorspace"
-      command << colorspace,
+      command << colorspace
       command << "-interlace"
       command << "none"
       command << "-density"
-      command << density.to_s,
+      command << density.to_s
       command << "#{Shellwords.shellescape(pdf.path)}[#{index}]"
       command << path
 

spec/lib/grim_spec.rb

@@ -25,10 +25,6 @@
   it "should have COLORSPACE constant set to 'RGB'" do
     expect(Grim::COLORSPACE).to eq('RGB')
   end
-  
-  it "should have ALPHA constant set to 'Set'" do
-    expect(Grim::ALPHA).to eq('')
-  end
 
   describe "#reap" do
     it "should return an instance of Grim::Pdf" do