cros deploy: don't suggest cros-workon for non-workon'able CP

http://crrev.com/c/2373849 added a new warning, but didn't restrict it
to cros-workon'able packages.

BUG=none
TEST=`cros deploy -n ${HOST} crda` -> non-workon, no warning
TEST=`cros deploy -n ${HOST} shill` -> workon, not work'ed-on,
     WARNING
TEST=`cros-workon-${BOARD} start shill; cros deploy -n ${HOST} shill`,
     workon, but not rebuilt --> no warning (existing bug)
TEST=`scripts/run_pytest cli/deploy_unittest.py`

Change-Id: I3b20c9867583d35d591efbf28e4fea5c91f5653e
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/2809693
Tested-by: Brian Norris <briannorris@chromium.org>
Commit-Queue: Brian Norris <briannorris@chromium.org>
Reviewed-by: Kimiyuki Onaka <kimiyuki@google.com>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
diff --git a/cli/deploy.py b/cli/deploy.py
index 8d01e60..2c9cb1e 100644
--- a/cli/deploy.py
+++ b/cli/deploy.py
@@ -1228,10 +1228,11 @@
 
       # Warn when the user installs & didn't `cros workon start`.
       if emerge:
+        all_workon = workon_helper.WorkonHelper(sysroot).ListAtoms(use_all=True)
         worked_on_cps = workon_helper.WorkonHelper(sysroot).ListAtoms()
         for package in listed:
           cp = package_info.SplitCPV(package).cp
-          if cp not in worked_on_cps:
+          if cp in all_workon and cp not in worked_on_cps:
             logging.warning(
                 'Are you intentionally deploying unmodified packages, or did '
                 'you forget to run `cros workon --board=$BOARD start %s`?', cp)