PDB-307 Remove usage of bundler for ruby-1.8.5

Bundler times out on ruby-1.8.5. This is probably due to the fact that it is
such an old implementation. We are less concerned with latest gems for 1.8.5
so for now I'm disabling this functionality.

Signed-off-by: Ken Barber <ken@bob.sh>
Merge pull request #804 from kbarber/ticket/1.5.x/PDB-307-nobundler-for-ruby185

PDB-307 Remove usage of bundler for ruby-1.8.5