Fix shebang handling for empty files. References #2927.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@3258 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

railties/lib/rails_generator/commands.rb

@@ -220,12 +220,11 @@ module Rails
               if block_given?
                 df.write(yield(sf))
               else
-                line = sf.gets || ''
                 if file_options[:shebang]
                   df.puts("#!#{file_options[:shebang]}")
-                  df.puts(line) if line !~ /^#!/
-                else
-                  df.puts(line)
+                  if line = sf.gets
+                    df.puts(line) if line !~ /^#!/
+                  end
                 end
                 df.write(sf.read)
               end