PDB-307 Ensure 'vendor' directory is created for ruby 1.8.5 bundler

Signed-off-by: Ken Barber <ken@bob.sh>
Merge pull request #803 from kbarber/ticket/1.5.x/PDB-307-create_vendor_dir_for_ruby185_bundler

PDB-307 Ensure 'vendor' directory is created for ruby 1.8.5 bundler