bad header doxygen: ap_rflush does not return the number

of bytes flushed, it returns 0 on success, -1 on error.

Should be CTR.

Backport of rr1368393 and r1368396 from trunk.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1371930 13f79535-47bb-0310-9956-ffa450edef68