[rubygems/rubygems] Let original EACCES error be raised

This block of code already wraps file operations with
`SharedHelpers.filesystem_access`, which rescues and re-raises more
friendly errors. Also, I'm not fully sure creating a temporary directory
can end up raising an `Errno::EACCES` error from reading `tmpdir`
sources. Finally, this rescue block apparently leads to some false
positives when firewall is blocking the ruby executable on Windows, or
at least that's what we've got reported.

In any case, I think it's best to let the original error be raised.

https://github.com/rubygems/rubygems/commit/f7dbe54404

lib/bundler/compact_index_client/updater.rb

@@ -76,11 +76,6 @@ module Bundler
 
           update(local_path, remote_path, :retrying)
         end
-      rescue Errno::EACCES
-        raise Bundler::PermissionError,
-          "Bundler does not have write access to create a temp directory " \
-          "within #{Dir.tmpdir}. Bundler must have write access to your " \
-          "systems temp directory to function properly. "
       rescue Zlib::GzipFile::Error
         raise Bundler::HTTPError
       end

spec/bundler/bundler/compact_index_client/updater_spec.rb

@@ -36,16 +36,6 @@ RSpec.describe Bundler::CompactIndexClient::Updater do
     end
   end
 
-  context "when bundler doesn't have permissions on Dir.tmpdir" do
-    it "Errno::EACCES is raised" do
-      allow(Bundler::Dir).to receive(:mktmpdir) { raise Errno::EACCES }
-
-      expect do
-        updater.update(local_path, remote_path)
-      end.to raise_error(Bundler::PermissionError)
-    end
-  end
-
   context "when receiving non UTF-8 data and default internal encoding set to ASCII" do
     let(:response) { double(:response, :body => "\x8B".b) }