Revert "Collect release files with git gem."

This reverts commit 30c90d2.

requiring gem from gemspec does not work...

httpclient.gemspec

@@ -1,7 +1,4 @@
 require 'rubygems'
-require 'git'
-git = Git.open(File.dirname(__FILE__))
-files = git.ls_files.keys
 Gem::Specification.new { |s|
   s.name = "httpclient"
   s.version = "2.2.4"
@@ -11,8 +8,6 @@ Gem::Specification.new { |s|
   s.homepage = "http://github.com/nahi/httpclient"
   s.platform = Gem::Platform::RUBY
   s.summary = "gives something like the functionality of libwww-perl (LWP) in Ruby"
-  s.files = files
-  s.test_files = files.grep(/^test\/test_.*\.rb$/)
+  s.files = Dir.glob('{lib,sample,test}/**/*') + ['README.txt']
   s.require_path = "lib"
-  s.add_development_dependency "git"
 }