core_output_filter: don't split the brigade after a FLUSH bucket if it's the

last bucket.  This prevents creating unneccessary empty brigades which may
not be destroyed until the end of a keepalive connection.

Submitted by:	Juan Rivera <Juan.Rivera@NO_SPAM.citrix.com>


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@100210 13f79535-47bb-0310-9956-ffa450edef68