bots: Fix behavior when no merged key in item
bots: Fix behavior when no merged key in item

This fixes an intermittent exception that shows up when there's
no "merged" key in a test log item:

    File "/build/cockpit/bots/tests-data", line 253, in seed
      if pull and item["merged"] not in [ True, False ]:
    KeyError: 'merged'

andreasn/cockpit,garrett/cockpit,martinpitt/cockpit,SotolitoLabs/cockpit,cockpit-project/cockpit,mareklibra/cockpit,andreasn/cockpit,martinpitt/cockpit,cockpituous/cockpit,martinpitt/cockpit,stefwalter/cockpit,moraleslazaro/cockpit,moraleslazaro/cockpit,cockpit-project/cockpit,mvollmer/cockpit,mareklibra/cockpit,moraleslazaro/cockpit,mvollmer/cockpit,garrett/cockpit,mareklibra/cockpit,mvollmer/cockpit,SotolitoLabs/cockpit,andreasn/cockpit,mareklibra/cockpit,deryni/cockpit,deryni/cockpit,mvollmer/cockpit,cockpituous/cockpit,SotolitoLabs/cockpit,cockpituous/cockpit,cockpituous/cockpit,martinpitt/cockpit,deryni/cockpit,cockpit-project/cockpit,mvollmer/cockpit,mareklibra/cockpit,mareklibra/cockpit,garrett/cockpit,garrett/cockpit,cockpituous/cockpit,moraleslazaro/cockpit,SotolitoLabs/cockpit,deryni/cockpit,andreasn/cockpit,stefwalter/cockpit,stefwalter/cockpit,garrett/cockpit,deryni/cockpit,stefwalter/cockpit,deryni/cockpit,SotolitoLabs/cockpit,andreasn/cockpit,moraleslazaro/cockpit,stefwalter/cockpit,cockpit-project/cockpit,deryni/cockpit,stefwalter/cockpit,martinpitt/cockpit,SotolitoLabs/cockpit,SotolitoLabs/cockpit,moraleslazaro/cockpit,mareklibra/cockpit,cockpit-project/cockpit,andreasn/cockpit,stefwalter/cockpit,cockpituous/cockpit,moraleslazaro/cockpit,andreasn/cockpit