qemu: Alter error path cleanup for qemuDomainAttachChrDevice
qemu: Alter error path cleanup for qemuDomainAttachChrDevice

Based on recent review comment - rather than have a spate of goto failxxxx,
change to a boolean based model. Ensures that the original error can be
preserved and cleanup is a bit more orderly if more objects are added.

taget/libvirt,libvirt/libvirt,jardasgit/libvirt,jardasgit/libvirt,datto/libvirt,jfehlig/libvirt,zippy2/libvirt,taget/libvirt,libvirt/libvirt,taget/libvirt,jardasgit/libvirt,nertpinx/libvirt,nertpinx/libvirt,zippy2/libvirt,crobinso/libvirt,fabianfreyer/libvirt,datto/libvirt,taget/libvirt,nertpinx/libvirt,jardasgit/libvirt,eskultety/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,VenkatDatta/libvirt,crobinso/libvirt,eskultety/libvirt,fabianfreyer/libvirt,olafhering/libvirt,libvirt/libvirt,eskultety/libvirt,VenkatDatta/libvirt,eskultety/libvirt,zippy2/libvirt,nertpinx/libvirt,datto/libvirt,VenkatDatta/libvirt,datto/libvirt,olafhering/libvirt,crobinso/libvirt,olafhering/libvirt,crobinso/libvirt,andreabolognani/libvirt,VenkatDatta/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,taget/libvirt,andreabolognani/libvirt,andreabolognani/libvirt,jfehlig/libvirt,eskultety/libvirt,jfehlig/libvirt,VenkatDatta/libvirt,andreabolognani/libvirt,zippy2/libvirt,libvirt/libvirt,jardasgit/libvirt,jfehlig/libvirt,datto/libvirt,fabianfreyer/libvirt,olafhering/libvirt