[autotest] Support updating both firmware and CrOS from run_suite

Add firmware_build option for run_suite to pass in firmware build.
Save the build containing server-side test to job_keyvals.

Design doc:
https://docs.google.com/a/google.com/document/d/115aAHyZaatFDzuKWm61Sj2fImH4NDWikXqifvWKbbW0/edit#

BUG=chromium:270258
TEST=local run_suite:
make sure it works with older build:
./run_suite.py -b veyron_jerry -i trybot-veyron_jerry-paladin/R45-7086.0.0-b8  -p suites -s dummy_server

Call failed as --firmware_ro_build not supported yet.
./run_suite.py -b veyron_jerry -i trybot-veyron_jerry-paladin/R45-7122.0.0-b11 --firmware_build veyron_jerry-firmware/R41-6588.9.0 --test_source_build  trybot-veyron_jerry-paladin/R45-7122.0.0-b11 --firmware_ro_build veyron_jerry-firmware/R41-6588.9.0  -p suites -s dummy_server

Call failed as the firmware build does not have test_suites package built:
./run_suite.py -b veyron_jerry -i trybot-veyron_jerry-paladin/R45-7122.0.0-b11 --firmware_build veyron_jerry-firmware/R41-6588.9.0 --test_source_build  veyron_jerry-firmware/R41-6588.9.0 -p suites -s dummy_server

make sure it works with new build:
./run_suite.py -b veyron_jerry -i trybot-veyron_jerry-paladin/R45-7122.0.0-b11 --firmware_build veyron_jerry-firmware/R41-6588.9.0 --test_source_build  trybot-veyron_jerry-paladin/R45-7122.0.0-b11 -p suites -s dummy_server

DEPLOY=apache,scheduler

Change-Id: I50d23a7e81e4d6224b3483111110f910eb407074
Reviewed-on: https://chromium-review.googlesource.com/272793
Reviewed-by: Dan Shi <dshi@chromium.org>
Commit-Queue: Dan Shi <dshi@chromium.org>
Trybot-Ready: Dan Shi <dshi@chromium.org>
Tested-by: Dan Shi <dshi@chromium.org>
diff --git a/server/cros/provision.py b/server/cros/provision.py
index e254903..be90671 100644
--- a/server/cros/provision.py
+++ b/server/cros/provision.py
@@ -15,6 +15,7 @@
 ### Constants for label prefixes
 CROS_VERSION_PREFIX = 'cros-version'
 FW_VERSION_PREFIX = 'fw-version'
+FW_RO_VERSION_PREFIX = 'fwro-version'
 
 # Default number of provisions attempts to try if we believe the devserver is
 # flaky.