Replace BoundedInt with WSME's IntegerType

WSME has contained IntegerType class since version 0.6.
The class has been tested in WSME, and it is almost the same as
Ceilometer's BoundedInt class.
For the maintainability, this patch replaces BoundedInt class with
WSME's IntegerType class.

Change-Id: I8444d54c0bc53aec26dad57645f3f6e3f9867f01
Merge "Replace BoundedInt with WSME's IntegerType"