update test version of Rails to 4.0.5
Changes corresponding to changes in Rails 4.1 to support MySQL 5.7.3.

Commit in ActiveRecord: https://github.com/rails/rails/commit/b6655885ef13cf8d1705dc9b5232846f0207febd:
Remove `DEFAULT NULL` for primary key column to support MySQL 5.7.3
Since MySQL 5.7.3 m13 does now allow primary key column is null.
allow Rails version to be either 4.0 or 4.1
query the adapters' default pk instead of assuming its value

The mysql adapter's default primary key definition changed in 4.1 so we
can't assume that it's a fixed string anymore.  We now query the adapter
before we start testing and use that value to check that we haven't
modified anything.

NOTE: we'll need to be more subtle about changing the default PK value,
too.  We should modify the PK string instead of replacing it with a
hard-coded one.
patch mysql column spec instead of replacing it

Now that Rails 4.1 uses a different column definition spec for mysql
than Rails 4.0 did, we need to massage the string rather than just
dropping a constant string in its place.  We gsub the int(11) into a
bigint(20) and leave the rest of the string alone.
prepare for 1.1.0 release