Fix listing changes over SSH for 2.14

The SSH query API changed from 2.13 to 2.14 from

{"number":"1", ...}

to

{"number":1, ...}

so we need to stringify everything in order to do len, encode etc. on
it.

Change-Id: I06bdd1b4b1181d00a27ce1e76f97baed8cde1284
Story: 2001095

git_review/cmd.py

@@ -1028,7 +1028,7 @@ class ReviewsPrinter(object):
     @property
     def fields_width(self):
         return [
-            max(len(review[field]) for review in self.reviews)
+            max(len(str(review[field])) for review in self.reviews)
             for field in self.fields[:-1]
         ] + [1]