Choose "-D" instead of "-d" for the rotatelogs

Choose "-D" instead of "-d" for the rotatelogs
option that creates the path to the log file.

I want to use "-d" for another directory related
option next where (I think) the "directory" "d"
makes more sense.

"-d" has not yet been backported, so changing
to "-D" is not a real compatibility issue.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1666417 13f79535-47bb-0310-9956-ffa450edef68