[DRE-maint] Bug#992040: gitlab 2FA broken: NoMethodError (undefined method `module_count' for #<RQRCode::QRCode:0x000055befdbc10a8>

[Pirate Praveen]

Package: gitlab
Version: 13.12.9+ds1-1
Severity: important

When trying to enable two factor authentication, gitlab shows a 500 
error and production.log has this error.

Started GET "/-/profile/two_factor_auth" for 192.168.122.1 at 
2021-08-09 16:19:49 +0000
Processing by Profiles::TwoFactorAuthsController#show as HTML
Completed 500 Internal Server Error in 349ms (ActiveRecord: 11.8ms | 
Elasticsearch: 0.0ms | Allocations: 84358)

NoMethodError (undefined method `module_count' for 
#<RQRCode::QRCode:0x000055befdbc10a8>
Did you mean? modules):

app/controllers/profiles/two_factor_auths_controller.rb:134:in 
`build_qr_code'
app/controllers/profiles/two_factor_auths_controller.rb:39:in `show'
app/controllers/application_controller.rb:490:in `set_current_admin'
lib/gitlab/session.rb:11:in `with_session'
app/controllers/application_controller.rb:481:in `set_session_storage'
lib/gitlab/i18n.rb:99:in `with_locale'
lib/gitlab/i18n.rb:105:in `with_user_locale'
app/controllers/application_controller.rb:475:in `set_locale'
app/controllers/application_controller.rb:468:in `block in 
set_current_context'
lib/gitlab/application_context.rb:70:in `block in use'
lib/gitlab/application_context.rb:70:in `use'
lib/gitlab/application_context.rb:27:in `with_context'
app/controllers/application_controller.rb:459:in `set_current_context'
lib/gitlab/middleware/speedscope.rb:13:in `call'
lib/gitlab/request_profiler/middleware.rb:17:in `call'
lib/gitlab/jira/middleware.rb:19:in `call'
lib/gitlab/middleware/go.rb:20:in `call'
lib/gitlab/etag_caching/middleware.rb:21:in `call'
lib/gitlab/middleware/multipart.rb:172:in `call'
lib/gitlab/middleware/read_only/controller.rb:50:in `call'
lib/gitlab/middleware/read_only.rb:18:in `call'
lib/gitlab/middleware/same_site_cookies.rb:27:in `call'
lib/gitlab/middleware/handle_malformed_strings.rb:21:in `call'
lib/gitlab/middleware/basic_health_check.rb:25:in `call'
lib/gitlab/middleware/handle_ip_spoof_attack_error.rb:25:in `call'
lib/gitlab/middleware/request_context.rb:21:in `call'
config/initializers/fix_local_cache_middleware.rb:11:in `call'
lib/gitlab/middleware/rack_multipart_tempfile_factory.rb:19:in `call'
lib/gitlab/metrics/requests_rack_middleware.rb:76:in `call'
lib/gitlab/middleware/release_env.rb:12:in `call'
Started GET "/favicon.ico" for 192.168.122.1 at 2021-08-09 16:19:49 
+0000