add before_test scripts

Solves the following message

Msg 922, Level 14, State 1, Server APPVYR-WIN20122\SQL2012SP1, Line 1
361Database 'model' is being recovered. Waiting until recovery is finished.

Soltution comes from https://gist.github.com/jonathanhickford/1cb0d6665adab8b9c664
and a ticket is open here : http://help.appveyor.com/discussions/suggestions/264-database-mssqlsystemresource-is-being-recovered-waiting-for-sql-server-to-start
Merge pull request #5514 from antograssiot/3.0

3.0 add before_test scripts for appveyor