Fix quota limit range validator

In Quota model limit is defined with Integer type which in case of
MySQL and PostgreSQL is always stored in 4 bytes. At the same time,
the current validator checks that the value does not exceed sys.maxsize
which depends on whether the system is 32-bit or 64-bit based.

In SQLite Integer can be stored in 1, 2, 3, 4, 6, or 8 bytes depending
on the magnitude of the value. Nevertheless, assume that it can not
exceed 4 bytes for consistency.

Limited the upper bound of the validator with 2**31 - 1.

Added a unit test.

Closes-Bug: #1338479
Change-Id: Icefa2fc228e4255a022d586cab4590607953d1ee
Merge "Fix quota limit range validator"
Merge branch 'master' of https://github.com/openstack/quantum