Fixing tests with multiple Driver#config

As it creates a new driver each time.
Thanks @icholy
Using the proper nonsensical elasticsearch-ruby API

For configuring a custom adapter. Basically, Patron
was being solemnly ignored. Keep in mind that we
are stuck with version 0.4 of elasticsearch-ruby
because it supports v0.9 of ES API.
Merge pull request #46 from uken/patron-and-test-fixes

Patron and test fixes
use @timestamp for index