add input filter AP_MODE_INIT support to handshake before reading

request data from the client.
PR:
Obtained from:
Submitted by:	dougm
Reviewed by:	wrowe


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@92043 13f79535-47bb-0310-9956-ffa450edef68