Remove bundler install during Appveyor tests (#217)

It appears that the Appveyor images changed recently and the Ruby
installs for all version (2.2, 2.3, and 2.4) already include Bundler
installed. Attempting to install it will hang the tests at an
interactive prompt asking if you want to override the install, and
--force'ing the install causes path issues and Rubygems won't be able
to activate the gem.

Removing the bundler install appears to solve the problem nicely.

Signed-off-by: Adam Leff <[email protected]>

appveyor.yml

@@ -6,7 +6,6 @@ platform:
 environment:
   winrm_user: test_user
   winrm_pass: Pass@word1
-  bundler_url: https://rubygems.org/downloads/bundler-1.9.9.gem
 
   matrix:
     - ruby_version: "22"
@@ -40,8 +39,6 @@ install:
   - ps: Write-Host $env:PATH
   - ruby --version
   - gem --version
-  - appveyor DownloadFile -Url %bundler_url% -FileName bundler.gem
-  - gem install --local bundler --quiet --no-document
   - bundler --version
   - ruby -r rubygems -e "p Gem.path"