Disable usage of git in gemspec, preventing gemspec installation.

Index: ruby-faraday/faraday.gemspec
===================================================================
--- ruby-faraday.orig/faraday.gemspec
+++ ruby-faraday/faraday.gemspec
@@ -16,5 +16,5 @@ Gem::Specification.new do |spec|
 
   spec.add_dependency 'multipart-post', '>= 1.2', '< 3'
 
-  spec.files = `git ls-files -z lib LICENSE.md README.md`.split("\0")
+  spec.files = Dir.glob('{lib}/**/*') + %w(LICENSE.txt README.md)
 end