base: Use a normal error for HTTP channel problems
base: Use a normal error for HTTP channel problems

Don't use HttpError() exceptions when the failure was the result
of a standard cockpit channel problem.

This simplifies the code, and uses a common object for channel problems.

Closes #1833
Reviewed-by: Marius Vollmer <bb11c6e942c5cc765df5f04da146b3198127a7a3@redhat.com>

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