Fixes issue with bundler.
* test/rubygems/test_gem_package.rb: Test for above.
* lib/rubygems/remote_fetcher.rb: Only update the cache when we have
permission. [ruby-trunk - Bug #7509]
* lib/rubygems/source.rb (class Gem): ditto
* test/rubygems/test_gem_remote_fetcher.rb: Test for above.
* lib/rubygems/test_utilities.rb: ditto
* lib/rubygems/specification.rb: Derive base_dir properly for default
gems. [ruby-trunk - Bug #7496]
* test/rubygems/test_gem_specification.rb: Test for above.
* lib/rubygems.rb: Untaint Dir.pwd when searching for gemdeps files
for operation under $SAFE=1
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@38229 b2dd03c8-39d4-4d8f-98ff-823fe69b080e