THRIFT-2491 unable to import generated ThriftTest service

Client: Go
Patch: Aleksey Pesternikov

This closes #105

commit f2e7186ca8d63f407dba0c56ee51afd6405926ba
 Author: Aleksey Pesternikov <ap@alekseys-mbp.att.net>
 Date: 2014-04-22T12:48:14Z

add _ to generated filename if it ends with _test.go