Move RPM repair code into SiteHost.

This moves handling specific to the Chrome OS lab infrastructure
into a Chromium OS specific file.

BUG=chromium-os:35804
TEST=Run repair on a broken unit with a local config; see RPM fail to repair it

Change-Id: I363730597aab46751b55ae9d1324353b8800244d
Reviewed-on: https://gerrit.chromium.org/gerrit/38393
Tested-by: Richard Barnette <jrbarnette@chromium.org>
Reviewed-by: Chris Sosa <sosa@chromium.org>
Reviewed-by: Simran Basi <sbasi@chromium.org>
Reviewed-by: Scott Zawalski <scottz@chromium.org>
Commit-Ready: Richard Barnette <jrbarnette@chromium.org>
diff --git a/global_config.ini b/global_config.ini
index b1fd919..bafb403 100644
--- a/global_config.ini
+++ b/global_config.ini
@@ -154,4 +154,4 @@
 rpm_sentry_username: fake_user
 rpm_sentry_password: fake_password
 rpm_frontend_uri: http://chromeos-rpmserver1.cbf.corp.google.com:9999
-boards_with_recovery: stumpy,kiev
+rpm_recovery_boards: stumpy,kiev