Remove 60 secs subtraction from item_expires

According to https://github.com/gholt/swauth/issues/73 nobody
knows why is this here. Let's try to remove it :).

Change-Id: I6de2c7eca5b7c4cbed61c966149055705efe8323

swauth/middleware.py

@@ -1447,7 +1447,7 @@ class Swauth(object):
                 TRUE_VALUES:
             self.itoken = '%sitk%s' % (self.reseller_prefix, uuid4().hex)
             memcache_key = '%s/auth/%s' % (self.reseller_prefix, self.itoken)
-            self.itoken_expires = time() + self.token_life - 60
+            self.itoken_expires = time() + self.token_life
             memcache_client = cache_from_env(env)
             if not memcache_client:
                 raise Exception(