refactored code based on feedback plus fixed a couple of other issues

...e/20160302152808_remove_wrong_import_url_from_projects.rb

lib/gitlab/bitbucket_import/client.rb

lib/gitlab/bitbucket_import/importer.rb

lib/gitlab/bitbucket_import/importer_init.rb

lib/gitlab/bitbucket_import/key_deleter.rb

lib/gitlab/google_code_import/importer.rb

lib/gitlab/google_code_import/project_creator.rb

spec/lib/gitlab/google_code_import/importer_spec.rb