sshwatcher: Do not eat stderr.

Sometimes there's useful error messages in stderr.

BUG=None
TEST=sshwatcher.go volteerhome 2022 ...

Change-Id: Ia089193dd00eb1fc419720f8db4648c3824ff33a
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/3641187
Reviewed-by: Satoshi Niwa <[email protected]>
Tested-by: Junichi Uekawa <[email protected]>
Commit-Queue: Junichi Uekawa <[email protected]>
1 file changed