[gerrit] `git review -l` can not list the open reviews

[John Wang]

Hi,
When I used `git review -l` to see the open reviews,`git review`
aborted.
Log:
```
 File "/usr/bin/git-review", line 10, in <module>
    sys.exit(main())
  File "/usr/lib/python2.7/dist-packages/git_review/cmd.py", line 1522, in main
    _main()
  File "/usr/lib/python2.7/dist-packages/git_review/cmd.py", line 1447, in _main
    list_reviews(remote)
  File "/usr/lib/python2.7/dist-packages/git_review/cmd.py", line 973,
in list_reviews
    review_field_width[i] = max(len(r[i]) for r in review_list)
  File "/usr/lib/python2.7/dist-packages/git_review/cmd.py", line 973,
in <genexpr>
    review_field_width[i] = max(len(r[i]) for r in review_list)
TypeError: object of type 'int' has no len()
```
$ git review --version
git-review version 1.25.0

`git review -l` works fine on an old gerrit version.

Has anyone encountered this problem and how should it be solved?

Thanks

John