Arvados

According to the 288f0787acbee74105540185389e3ffa1c614f3f commit message, parts of our test infrastructure assume they can just run bundle after installing the arvados-api-server package. But arvados-api-server really wants to carve out its own special way to run Bundler. If other code wants to use that Bundle install, it should invoke it the same way RailsAPI does.

• Remove the Bundler wrappers in /usr/local/bin from the arvados-api-server postinst.
• Update source:build/package-testing/test-package-arvados-api-server.sh to invoke the specific Bundler installed by the postinst script.
• If anything else breaks after doing that, fixing it is explicitly in scope for this ticket.