$QEMU_PROG happens to be 'qemu' in my setup, so this sed command
replaces a bit too much. Restrict it to the start of the line and to
when it's followed by a colon, i.e. the form used by error messages.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NStefan Hajnoczi <stefanha@redhat.com>