Fix 500 from account-quota middleware

If a user had set X-Account-Meta-Quota-Bytes to something non-integer
prior to the installation of the account-quota middleware, then the
quota check would choke on it. Now a non-integer value is treated as
"no quota".

Change-Id: I5c38911be1f66fa293aea9c78590d4ce7d184113
return value on memcache client decr call

Closes-Bug: 1238204
Change-Id: I7d2ece118159637e5c5bf4bf5dd4ce4d2f6e4523
Removes vim comment

Change-Id: Ibc930638ee2d839e8499a13018c205b615f8b854
Partial-Bug: 1229324
Merge "Removes vim comment"
Merge "Fix 500 from account-quota middleware"