Add more (trace) logging to the ap_scan_script_header*() functions

Add ap_scan_script_header*_ex() functions that take a module index for
logging.
Make mod_cgi, mod_cgid, mod_proxy_fcgi, mod_proxy_scgi, mod_isapi use the
new functions.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1147493 13f79535-47bb-0310-9956-ffa450edef68