Switch to master branch which provides Version 1.3.x of AR-JDBC adapter.
It strives to provide ActiveRecord 4.x compatibility (as well as still supporting 2.3 and 3.x) from a single code base. It's a recommended update for all AR-JDBC 1.2.x users.

Fixes #11457

- https://travis-ci.org/rails/rails/jobs/7264822 contains deprecated
  warnings given by Mocha version 0.14
- 632f215d added Mocha 0.14 to Gemfile
- But with the version, require: false was removed
- So Mocha started giving deprecation warnings
- Acc.to Mocha documentation(https://github.com/freerange/mocha#bundler)
  it should not be auto required.

Related with 57583879

This reverts commit 6f3f0f86.

See
https://github.com/wycats/thor/commit/08265a380d0ff3fce014e98e87bb8c2330858e4a
for the discussion and https://github.com/wycats/thor/pull/316 for the
fix

Using latest AR-JDBC for JRuby

The dependency was introduced in this commit:

002713c6

which has been released a long time ago

This reverts commit 9c18b6a8.

This reverts commit fba97c96.