fix(image_to_vm): Cleanup qemu script, document -virtfs
fix(image_to_vm): Cleanup qemu script, document -virtfs

smilart/scripts,endocode/scripts,mischief/scripts,sigma/coreos-scripts,coreos/scripts,nicescale/scripts,coreos/scripts,sigma/coreos-scripts,mjg59/scripts,trnubo/scripts,glevand/coreos--scripts,crawford/scripts,mjg59/scripts,trnubo/scripts,vmware/coreos-scripts,fivethreeo/scripts,mischief/scripts,endocode/scripts,marineam/coreos-scripts,fivethreeo/scripts,crawford/scripts,crawford/scripts,glevand/coreos--scripts,BugRoger/scripts,gtank/scripts,BugRoger/scripts,nicescale/scripts,BugRoger/scripts,vmware/coreos-scripts,sigma/coreos-scripts,mjg59/scripts,vmware/coreos-scripts,andrejro/coreos--scripts,bcwaldon/coreos-scripts,gtank/scripts,fivethreeo/scripts,endocode/scripts,andrejro/coreos--scripts,marineam/coreos-scripts,bcwaldon/coreos-scripts,gtank/scripts,zhang0137/scripts,smilart/scripts,bcwaldon/coreos-scripts,zhang0137/scripts,marineam/coreos-scripts,smilart/scripts,trnubo/scripts,nicescale/scripts,mischief/scripts,zhang0137/scripts,andrejro/coreos--scripts