deploy_unittest: fix tests under Python 3

We use & assume num_updates is a number everywhere, including 0.
The unittest sets it to None for some reason which doesn't work
as Python 3 doesn't allow comparing None to ints with < and >.

BUG=chromium:997354
TEST=`./run_tests` passes

Change-Id: I0dc4315f2f5baf459911c52d0fb54d182a36a49b
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/1935251
Reviewed-by: Jack Rosenthal <jrosenth@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
diff --git a/cli/deploy_unittest.py b/cli/deploy_unittest.py
index 3dce908..fc7927b 100644
--- a/cli/deploy_unittest.py
+++ b/cli/deploy_unittest.py
@@ -115,7 +115,7 @@
     self.pkgs = packages
     self.cpvs = packages_cpvs or packages
     self.listed = []
-    self.num_updates = None
+    self.num_updates = 0
     self.pkgs_attrs = pkgs_attrs
 
   def Run(self, _device, _root, _packages, _update, _deep, _deep_rev):