Cloned from https://bugzilla.redhat.com/show_bug.cgi?id=1474293

Description of problem:
Our automation hit yet another race condition on registering the hosts simultaneously (2 hosts).
See attached foreman-debug:
production.log - see requests: 4c6a15a5 and 64762ef4 (which failed) (2017-07-20 21:05:54)

2017-07-20 21:05:51 64762ef4 [app] [I] Started POST "/rhsm/consumers?owner=Ag72NG&activation_keys=IsRwhiODa7" for 10.8.30.229 at 2017-07-20 21:05:51 -0400
2017-07-20 21:05:51 64762ef4 [app] [I] Processing by Katello::Api::Rhsm::CandlepinProxiesController#consumer_activate as JSON
...
...
2017-07-20 21:05:54 [audit] [I] [140318963445328.lab.eng.rdu2.redhat.com] added 153 (3963.0ms)
2017-07-20 21:05:54 [app] [I] Import facts for '140318963445328.lab.eng.rdu2.redhat.com' completed. Added: 153, Updated: 0, Deleted 0 facts
2017-07-20 21:05:54 [app] [E] Fact dmi::system::uuid could not be imported because of PG::Error: ERROR: duplicate key value violates unique constraint "index_fact_names_on_name_and_type" | : INSERT INTO "fact_names" ("compose", "created_at", "name", "short_name", "type", "updated_at") VALUES ($1, $2, $3, $4, $5, $6) RETURNING "id"
2017-07-20 21:05:54 [app] [E] Fact distribution::name could not be imported because of PG::Error: ERROR: current transaction is aborted, commands ignored until end of transaction block | : SELECT "fact_names".* FROM "fact_names" WHERE "fact_names"."type" IN ('Katello::RhsmFactName') AND "fact_names"."name" = 'distribution' AND "fact_names"."type" = 'Katello::RhsmFactName' ORDER BY fact_names.name LIMIT 1
...
...
2017-07-20 21:05:55 [audit] [I] [140599713026320.lab.eng.rdu2.redhat.com] added 166 (1966.6ms)
2017-07-20 21:05:55 [app] [W] Error during fact import for 140599713026320.lab.eng.rdu2.redhat.com | ActiveRecord::StatementInvalid: PG::Error: ERROR: current transaction is aborted, commands ignored until end of transaction block | : SELECT "fact_names".* FROM "fact_names" WHERE "fact_names"."type" IN ('Katello::RhsmFactName') AND "fact_names"."name" = 'memor | /opt/rh/rh-ror41/root/usr/share/gems/gems/activerecord-4.1.5/lib/active_record/connection_adapters/postgresql_adapter.rb:822:in `ex | /opt/rh/rh-ror41/root/usr/share/gems/gems/activerecord-4.1.5/lib/active_record/connection_adapters/postgresql_adapter.rb:822:in `bl
...
...
2017-07-20 21:05:55 [foreman-tasks/action] [E] ERF50-2486 [Foreman::WrappedException]: Import of facts failed for host 14059971302632 | /usr/share/foreman/app/services/fact_importer.rb:48:in `import!'
... | /opt/theforeman/tfm/root/usr/share/gems/gems/concurrent-ruby-1.0.0/lib/concurrent/executor/ruby_thread_pool_executor.rb:304:in `blo | /opt/theforeman/tfm/root/usr/share/gems/gems/logging-1.8.2/lib/logging/diagnostic_context.rb:323:in `call' | /opt/theforeman/tfm/root/usr/share/gems/gems/logging-1.8.2/lib/logging/diagnostic_context.rb:323:in `block in create_with_logging_c
2017-07-20 21:05:56 64762ef4 [app] [I] Completed 500 Internal Server Error in 5045ms (Views: 0.6ms | ActiveRecord: 92.5ms)
2017-07-20 21:05:57 4c6a15a5 [app] [I] Completed 200 OK in 9308ms (Views: 2.9ms | ActiveRecord: 45.2ms)

Version-Release number of selected component (if applicable):
6.2.11-1

How reproducible:
sometimes

Steps to Reproduce:
hard to reproduce, however:
1. get 2 different hosts register to the same satellite at the same time, with the same org, env and activation key
2. making katello more busy might help, in our case, there were some POST requests to Environments and Content Views made just after the register requests.

Actual results:
duplicate key value violates unique constraint "index_fact_names_on_name_and_type"