Remove whitespace from blank lines in rules.mk. This fixes Irix 6.5

PR:	6357
Submitted by:	Mike Abbott <mja@sgi.com>
Reviewed by:	Ryan Bloom


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@86107 13f79535-47bb-0310-9956-ffa450edef68