Fix tests for membership to use 'not in'

flake8 reports:

  E713 test for membership should be 'not in'

Change-Id: I4446be67c431b7267105b53478d2ceba2af758d7
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/254451
Tested-by: David Pursehouse <dpursehouse@collab.net>
Reviewed-by: Mike Frysinger <vapier@google.com>
diff --git a/gitc_utils.py b/gitc_utils.py
index b47e181..8b5b007 100644
--- a/gitc_utils.py
+++ b/gitc_utils.py
@@ -104,11 +104,11 @@
       if not proj.upstream and not git_config.IsId(proj.revisionExpr):
         proj.upstream = proj.revisionExpr
 
-      if not path in gitc_manifest.paths:
+      if path not in gitc_manifest.paths:
         # Any new projects need their first revision, even if we weren't asked
         # for them.
         projects.append(proj)
-      elif not path in paths:
+      elif path not in paths:
         # And copy revisions from the previous manifest if we're not updating
         # them now.
         gitc_proj = gitc_manifest.paths[path]