Revert "Ensure valid package names in generator and don't import 'fmt' if not used"
Revert "Ensure valid package names in generator and don't import 'fmt' if not used"

This reverts commit 2b70631399fa6d749f15c0e833eabcd446089663.

prashantv/go-thrift,nuance/go-thrift,i/go-thrift,wfxiang08/go-thrift,zhaojkun/go-thrift