[autotest] Map chromeos2-row{..}-rack{8..11} to hydra2

Map chromeos2-row{..}-rack{1..7} to hydra1
Map chromeos2-row{..}-rack{8..11} to hydra2

Add an entry of [hydra2] in rpm_config.ini

TEST=set up a local rpm server and make sure power-cycling works on
rpms behind hydra1, 2 or no hydra.
BUG=chromium:366526

Change-Id: I81b74841a292b292cdacf61fd208e29c2f11fafb
Reviewed-on: https://chromium-review.googlesource.com/200767
Reviewed-by: Fang Deng <fdeng@chromium.org>
Tested-by: Fang Deng <fdeng@chromium.org>
Commit-Queue: Fang Deng <fdeng@chromium.org>
2 files changed