Update packager.py invocation arguments.

This patch updates the packager.py invocation to reflect the
formal addition of an action command line argument.

BUG=chromium:285856
TEST=Run './build_packages --board=${BOARD} --withdev' locally
CQ-DEPEND=CL:446026

Change-Id: Ifb6332ae1d4b659a84709db924ebc9b90611ae56
Signed-off-by: Prashant Malani <pmalani@google.com>
Reviewed-on: https://chromium-review.googlesource.com/447304
Reviewed-by: Aviv Keshet <akeshet@chromium.org>
diff --git a/build_artifact.py b/build_artifact.py
index 2388d5a..85426f1 100755
--- a/build_artifact.py
+++ b/build_artifact.py
@@ -507,7 +507,7 @@
       os.makedirs(autotest_pkgs_dir)
 
     if not os.path.exists(os.path.join(autotest_pkgs_dir, 'packages.checksum')):
-      cmd = ['autotest/utils/packager.py', 'upload', '--repository',
+      cmd = ['autotest/utils/packager.py', '--action=upload', '--repository',
              autotest_pkgs_dir, '--all']
       try:
         subprocess.check_call(cmd, cwd=self.install_dir)