Call ap_pass_brigade() *before* soaking up stderr. The normal CGI

is going to write a bunch of stuff to stdout and nothing to stderr.
Reading stderr before processing the stdout pipe can cause deadlock if
the CGI fills the kernel buffer for stdout because the CGI will stall
writing to stdout while the httpd process will stall reading from the
CGI's stderr.

The NPH CGI behavior was unchanged.  If this is still a problem for NPH
CGIs, it was a problem before filtering too.

Also, get rid of a couple of unused variables in cgi_handler.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@86150 13f79535-47bb-0310-9956-ffa450edef68