vm: Remove unecessary format string
vm: Remove unecessary format string

We now use Debug instead of Debugf here, so we don't need that %s, we're
just outputting two strings.

Signed-off-by: Damien Lespiau <64bd3cb94f359c1a3ce68dae5e26b40578526277@intel.com>

clearcontainers/proxy,clearcontainers/proxy