hv_{kvp,vss}_daemon used to communicate with the corresponding kernel
drivers over netlink, but now they use char devices. hv_fcopy_daemon
always used a char device. Rather than checking for Hyper-V
specifically, change all of the init scripts and systemd service
definitions to check for the appropriate device nodes.
Delete the check-hyperv program that we used to check for Hyper-V
in init scripts.
Ben Hutchings
Bastian Blank