Call system() with an array of arguments

This avoids using a shell and can deal properly with spaces in paths.

Author: ekohl

lib/fog/libvirt/models/compute/server.rb

@@ -260,7 +260,7 @@ def generate_config_iso_in_dir(dir_path, user_data, &blk)
           File.write(user_data_path, user_data)
 
           isofile = Tempfile.new(['init', '.iso']).path
-          unless system("xorrisofs -output #{isofile} -volid cidata -joliet -rock #{user_data_path} #{meta_data_path}")
+          unless system('xorrisofs', '-output', isofile, '-volid', 'cidata', '-joliet', '-rock', user_data_path, meta_data_path)
             raise Fog::Errors::Error.new("Couldn't generate cloud-init iso disk with xorrisofs.")
           end
           blk.call(isofile)

minitests/server/user_data_iso_test.rb

@@ -26,7 +26,7 @@ def test_contains_user_data_file
 
   def test_iso_is_generated
     in_a_temp_dir do |d|
-      @server.expects(:system).with(regexp_matches(/^xorrisofs/)).returns(true)
+      @server.expects(:system).with { |command, *_args| command == 'xorrisofs' }.returns(true)
       @server.generate_config_iso_in_dir(d, @test_data) {|iso| }
     end
   end