Content-Length header should always be interpreted as a decimal.

Leading 0  could be erroneously considered as an octal value. PR 56598.
[Chris Card <ctcard hotmail com>]

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1626086 13f79535-47bb-0310-9956-ffa450edef68