Avoid including apr_general.h.

The MSVC Resource Compiler truncates macro names at char 31.
Since apr_general.h includes apr.h which in turn includes
system headers we get warnings or errors with the Resource
Compiler with newer system headers (VC10 and later) which
have macro names defined with more than 31 chars.
(backport from trunk r1499742)
Reviewed by: gsmith, sf


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1499855 13f79535-47bb-0310-9956-ffa450edef68