hv_utils: Fix spelling mistake "Hearbeat" -> "Heartbeat"

There is a spelling mistake in an error message. Fix it.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20210127233136.623465-1-colin.king@canonical.com


Signed-off-by: Wei Liu <wei.liu@kernel.org>