Fix test for jh/spec/models/jh/vulnerabilities/finding_spec.rb

Remove unnecessary line of jh/spec/models/jh/vulnerabilities/finding_spec.rb and move jh/spec/models/jh/vulnerabilities/finding_spec.rb to jh/spec/models/vulnerabilities/finding_spec.rb

This line is copied from ee/spec/models/vulnerabilities/finding_spec.rb and upstream update this line after we merge !370 (merged), test failed.