qemu: Add coverity[negative_returns] tag
qemu: Add coverity[negative_returns] tag

This avoids "Event negative_returns: A negative constant "-1" is passed as
an argument to a parameter that cannot be negative.".  The called function
uses -1 to determine whether it needs to traverse all the hostdevs.

zippy2/libvirt,agx/libvirt,elmarco/libvirt,nertpinx/libvirt,eskultety/libvirt,zippy2/libvirt,VenkatDatta/libvirt,taget/libvirt,olafhering/libvirt,datto/libvirt,VenkatDatta/libvirt,cbosdo/libvirt,fabianfreyer/libvirt,eskultety/libvirt,taget/libvirt,elmarco/libvirt,elmarco/libvirt,jardasgit/libvirt,iam-TJ/libvirt,jardasgit/libvirt,shugaoye/libvirt,VenkatDatta/libvirt,elmarco/libvirt,trainstack/libvirt,agx/libvirt,taget/libvirt,cbosdo/libvirt,siboulet/libvirt-openvz,cbosdo/libvirt,VenkatDatta/libvirt,cbosdo/libvirt,crobinso/libvirt,zippy2/libvirt,fabianfreyer/libvirt,libvirt/libvirt,zhlcindy/libvirt-1.1.4-maintain,siboulet/libvirt-openvz,zhlcindy/libvirt-1.1.4-maintain,trainstack/libvirt,olafhering/libvirt,zippy2/libvirt,cbosdo/libvirt,agx/libvirt,nertpinx/libvirt,rlaager/libvirt,iam-TJ/libvirt,shugaoye/libvirt,trainstack/libvirt,datto/libvirt,libvirt/libvirt,rlaager/libvirt,eskultety/libvirt,nertpinx/libvirt,crobinso/libvirt,trainstack/libvirt,elmarco/libvirt,shugaoye/libvirt,datto/libvirt,fabianfreyer/libvirt,jfehlig/libvirt,trainstack/libvirt,olafhering/libvirt,olafhering/libvirt,shugaoye/libvirt,iam-TJ/libvirt,andreabolognani/libvirt,datto/libvirt,taget/libvirt,shugaoye/libvirt,andreabolognani/libvirt,zhlcindy/libvirt-1.1.4-maintain,iam-TJ/libvirt,VenkatDatta/libvirt,taget/libvirt,libvirt/libvirt,iam-TJ/libvirt,eskultety/libvirt,rlaager/libvirt,zhlcindy/libvirt-1.1.4-maintain,fabianfreyer/libvirt,eskultety/libvirt,datto/libvirt,jardasgit/libvirt,jardasgit/libvirt,crobinso/libvirt,trainstack/libvirt,crobinso/libvirt,nertpinx/libvirt,siboulet/libvirt-openvz,agx/libvirt,jfehlig/libvirt,jfehlig/libvirt,iam-TJ/libvirt,jfehlig/libvirt,andreabolognani/libvirt,libvirt/libvirt,iam-TJ/libvirt,rlaager/libvirt,siboulet/libvirt-openvz,trainstack/libvirt,andreabolognani/libvirt,zhlcindy/libvirt-1.1.4-maintain,fabianfreyer/libvirt,rlaager/libvirt,jardasgit/libvirt,siboulet/libvirt-openvz,andreabolognani/libvirt,nertpinx/libvirt,agx/libvirt