Fix a bug in setting maxtries

Noticed by Jens Widell in https://codereview.chromium.org/932333003/

TBR=maruel

BUG=459855

Review URL: https://codereview.chromium.org/933373004

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@294123 0039d316-1c4b-4281-b951-d872f2087c98

rietveld.py

@@ -600,7 +600,7 @@ class JwtOAuth2Rietveld(Rietveld):
     self._xsrf_token = None
     self._xsrf_token_time = None
 
-    self._maxtries = 40 or maxtries
+    self._maxtries = maxtries or 40
 
 
 class CachingRietveld(Rietveld):