shill: Import variables in shill init job.

Whitelist a bunch of parameters that the job allows to pass in via
upstart commands and events.

BUG=chromium:818032
TEST=Starting shill with the parameters in question doesn't generate undeclared import log messages.

Change-Id: I5825c12ad4c160e15c35f48f9ed1308cadee59fc
Reviewed-on: https://chromium-review.googlesource.com/1049560
Commit-Ready: Mattias Nissler <mnissler@chromium.org>
Tested-by: Mattias Nissler <mnissler@chromium.org>
Reviewed-by: Kevin Cernekee <cernekee@chromium.org>
diff --git a/init/shill.conf.in b/init/shill.conf.in
index 4cc5534..f49a1f4 100644
--- a/init/shill.conf.in
+++ b/init/shill.conf.in
@@ -40,12 +40,24 @@
 env SHILL_MINIMUM_MTU=
 env BLACKLISTED_DEVICES=
 env DHCPV6_ENABLED_DEVICES=
-env IGNORE_UNKNOWN_ETHERNET=
 env ARC_DEVICE=arcbr0
 
 # Hook for mod_for_test_scripts/100setupTestingInterface.
 env SHILL_TEST_DEVICES=""
 
+# Allow the parameters to be overridden by upstart commands and events.
+import ARC_DEVICE
+import BLACKLISTED_DEVICES
+import DHCPV6_ENABLED_DEVICES
+import SHILL_ACCEPT_HOSTNAME_FROM
+import SHILL_LOG_LEVEL
+import SHILL_LOG_SCOPES
+import SHILL_LOG_VMODULES
+import SHILL_MINIMUM_MTU
+import SHILL_PASSIVE_MODE
+import SHILL_PREPEND_DNS_SERVERS
+import SHILL_TEST_DEVICES
+
 pre-start exec /bin/sh /usr/share/cros/init/shill-pre-start.sh
 
 post-stop exec bootstat shill-stop