check_ethernet: reduce ping -c9 to -c3

Reducing "-c 9" to "-c 3" since ping doesn't return until all 9 ICMP
packets have been sent.  This is problematic since we retest
connectivity after each recovery method - could take several minutes
to run through everything in the failure case.

Also, if first ICMP packet doesn't get a response, the rest likely
won't either since we have reliable networking in the test lab. And
if the test lab network is unreliable in some racks, we want to know
since provisioning will take longer.

BUG=none
TEST=manually run ping commands

Change-Id: I5fd68c817ec88f641c0eba4e3097262be4d62ade
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crostestutils/+/2044953
Reviewed-by: Brian Norris <briannorris@chromium.org>
Reviewed-by: Grant Grundler <grundler@chromium.org>
Commit-Queue: Grant Grundler <grundler@chromium.org>
Tested-by: Grant Grundler <grundler@chromium.org>
1 file changed