Fix: Use "max_request_body_size" value as int instead of string

The CherryPy variable "max_request_body_size" should be a number value,
in bytes. The current code runs something like
"eval('max_body_size' * 1024)", where 'max_body_size' is the value read
from the external configuration file, in kilobytes. Multiplying a string
by a number in Python creates a new string repeating the original string
a number of times. We expect a multiplication, not a string repetition.
This bug was introduced by commit e3b79e3.

Multiply the number 1024 by another number (i.e. the "eval" result), not
a string.

Signed-off-by: Crístian Viana <vianac@linux.vnet.ibm.com>