devel/rubygem-generator_spec: Rename to devel/rubygem-generator_spec-rails5
and update to version 0.9.4

• devel/rubygem-generator_spec depended on Rails version 4, but there already is a devel/rubygem-generator_spec-rails4

• depend on activesupport instead of activerecord

Approved by: swills (mentor, implicit)