ws: Add precondition to cockpit_web_service_get_creds()
ws: Add precondition to cockpit_web_service_get_creds()

Fixes #669
Closes #688

Reviewed-by: Stef Walter <8a7fbf0f15d3ad982af54ef28f5c117d2494b76c@redhat.com>

vanloswang/cockpit,Armstrong1992/cockpit,vanloswang/cockpit,petervo/cockpit,dperpeet/cockpit,deryni/cockpit,martinpitt/cockpit,mareklibra/cockpit,jscotka/cockpit,arilivigni/cockpit,netzvieh/cockpit,jscotka/cockpit,larsu/cockpit,cockpituous/cockpit,zigitax/cockpit,cockpit-project/cockpit,vbatts/cockpit,moraleslazaro/cockpit,garrett/cockpit,mvollmer/cockpit,Scribery/cockpit,Thermionix/cockpit,harishanand95/cockpit,cockpit-project/cockpit,petervo/cockpit,Scribery/cockpit,haiyangd/cockpit_view,Armstrong1992/cockpit,fridex/cockpit,harishanand95/cockpit,deryni/cockpit,fridex/cockpit,dperpeet/cockpit,deryni/cockpit,larskarlitski/cockpit,martinpitt/cockpit,Scribery/cockpit,Thermionix/cockpit,evol262/cockpit,sgallagher/cockpit,firebitsbr/cockpit,xhad/cockpit,FireDrunk/cockpit,matobet/cockpit,mvollmer/cockpit,cockpit-project/cockpit,arilivigni/cockpit,arilivigni/cockpit,nmav/cockpit,moraleslazaro/cockpit,sub-mod/cockpit,xhad/cockpit,vbatts/cockpit,kkaempf/cockpit,andreasn/cockpit,netzvieh/cockpit,SotolitoLabs/cockpit,andreasn/cockpit,sgallagher/cockpit,Thermionix/cockpit,cockpit-project/cockpit,xhad/cockpit,darioajr/cockpit,netzvieh/cockpit,denysvitali/cockpit,petervo/cockpit,mareklibra/cockpit,darioajr/cockpit,dperpeet/cockpit,harishanand95/cockpit,larskarlitski/cockpit,larsu/cockpit,stefwalter/cockpit,cockpituous/cockpit,michalskrivanek/cockpit,netzvieh/cockpit,firebitsbr/cockpit,mareklibra/cockpit,SotolitoLabs/cockpit,cockpit-project/cockpit,moraleslazaro/cockpit,harishanand95/cockpit,stefwalter/cockpit,fridex/cockpit,mareklibra/cockpit,Scribery/cockpit,moolitayer/cockpit,stefwalter/cockpit,firebitsbr/cockpit,garrett/cockpit,stefwalter/cockpit,SotolitoLabs/cockpit,sgallagher/cockpit,nmav/cockpit,andreasn/cockpit,kkaempf/cockpit,dperpeet/cockpit,matobet/cockpit,nmav/cockpit,stefwalter/cockpit,maxamillion/cockpit,maxamillion/cockpit,dperpeet/cockpit,petervo/cockpit,Scribery/cockpit,denysvitali/cockpit,kkaempf/cockpit,vbatts/cockpit,Armstrong1992/cockpit,michalskrivanek/cockpit,Armstrong1992/cockpit,nmav/cockpit,xhad/cockpit,fridex/cockpit,moolitayer/cockpit,Thermionix/cockpit,denysvitali/cockpit,jscotka/cockpit,mvollmer/cockpit,larskarlitski/cockpit,Scribery/cockpit,deryni/cockpit,haiyangd/cockpit_view,zigitax/cockpit,jscotka/cockpit,vanloswang/cockpit,moolitayer/cockpit,Scribery/cockpit,evol262/cockpit,michalskrivanek/cockpit,mareklibra/cockpit,FireDrunk/cockpit,larsu/cockpit,zigitax/cockpit,Thermionix/cockpit,SotolitoLabs/cockpit,larskarlitski/cockpit,petervo/cockpit,andreasn/cockpit,maxamillion/cockpit,haiyangd/cockpit_view,haiyangd/cockpit_view,moraleslazaro/cockpit,michalskrivanek/cockpit,deryni/cockpit,larsu/cockpit,arilivigni/cockpit,garrett/cockpit,deryni/cockpit,arilivigni/cockpit,vbatts/cockpit,FireDrunk/cockpit,mareklibra/cockpit,matobet/cockpit,sgallagher/cockpit,moolitayer/cockpit,matobet/cockpit,sub-mod/cockpit,zigitax/cockpit,xhad/cockpit,martinpitt/cockpit,arilivigni/cockpit,haiyangd/cockpit_view,vanloswang/cockpit,larskarlitski/cockpit,mareklibra/cockpit,mvollmer/cockpit,nmav/cockpit,zigitax/cockpit,netzvieh/cockpit,vanloswang/cockpit,cockpituous/cockpit,denysvitali/cockpit,larsu/cockpit,sub-mod/cockpit,garrett/cockpit,larskarlitski/cockpit,dperpeet/cockpit,sub-mod/cockpit,jscotka/cockpit,larsu/cockpit,petervo/cockpit,darioajr/cockpit,matobet/cockpit,moraleslazaro/cockpit,Thermionix/cockpit,cockpituous/cockpit,sgallagher/cockpit,andreasn/cockpit,evol262/cockpit,denysvitali/cockpit,stefwalter/cockpit,vanloswang/cockpit,petervo/cockpit,darioajr/cockpit,maxamillion/cockpit,moolitayer/cockpit,arilivigni/cockpit,SotolitoLabs/cockpit,matobet/cockpit,vbatts/cockpit,andreasn/cockpit,kkaempf/cockpit,evol262/cockpit,mvollmer/cockpit,xhad/cockpit,SotolitoLabs/cockpit,cockpituous/cockpit,firebitsbr/cockpit,michalskrivanek/cockpit,harishanand95/cockpit,martinpitt/cockpit,stefwalter/cockpit,cockpituous/cockpit,larskarlitski/cockpit,sgallagher/cockpit,martinpitt/cockpit,FireDrunk/cockpit,fridex/cockpit,harishanand95/cockpit,jscotka/cockpit,deryni/cockpit,evol262/cockpit,michalskrivanek/cockpit,fridex/cockpit,moraleslazaro/cockpit,sub-mod/cockpit,michalskrivanek/cockpit,moraleslazaro/cockpit,SotolitoLabs/cockpit,maxamillion/cockpit,dperpeet/cockpit,kkaempf/cockpit,garrett/cockpit,andreasn/cockpit,darioajr/cockpit,harishanand95/cockpit,netzvieh/cockpit,vanloswang/cockpit,vbatts/cockpit,Armstrong1992/cockpit,sgallagher/cockpit,FireDrunk/cockpit,xhad/cockpit,evol262/cockpit,firebitsbr/cockpit