Pass tds_version to TinyTds::Client.new

I had some troubles with encoding. SQL Server 2005, encoding cp1251. I tried to use `tsql`, it worked. Then I checked version, and found that it worked with tds version 4.2 by default. So I tried to initialize TinyTds::Client with tds_version 42, and it worked fine too. Then, when I put `tds_version: '42'` into `config/database.yml`, it did not work, and I found that this option was not passed to TinyTds::Client.new. This small patch is intended to fix this issue.