common: Hold reference to CockpitPipe while emitting signals
common: Hold reference to CockpitPipe while emitting signals

While emitting CockpitPipe::read signal, hold a reference to
self, in case the signal handler unrefs the pipe, we can still
act in a coherent manner.

Caught by Travis and Valgrind.
Reviewed-by: Marius Vollmer <bb11c6e942c5cc765df5f04da146b3198127a7a3@redhat.com>

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