rm redundant preload() in failing test
partial fix issue #1053; bundles without locations err on path.join()
partial fix issue #1053; test unset path part data

also changed mock conf to always start with a clean copy
partial fix issue #1053; pass "" to test instead of nothing
partial fix issue #1053; use real addon/rs.url.js instead of mock.

back out previous `res.url || ''` guard. root cause of undefined
res.url in the unit tests was poor mock.
Merge pull request #1055 from isao/issue1053

fix issue 1053 non-string args to path.join err in 0.9.x/0.10.x