Remove the docker-machine-driver-kvm2 wrapper and use the kvm driver as
internal driver.
To avoid dependency on libvirt shared library on Linux, we build now
with the libvirt_dlopen build tag. This is used only linux to avoid
linking with libvirt shared library. This is not documnted but can be
found in the source.
f7cdeba997/domain.go (L30)
With this we don't need libvirt devel libraries during build, and in
runtime we will fail if libvirt shared library is not installed.
With this change minikube can not be built for linux !amd64 since building
libvirt go binding requires CGO, and it does not work by changing GOARCH.
7bc97d7ce1