a long time ago ...

REWRITELOCK_MODE wasn't used anymore for ages. In the meantime it defined
the mode of the rewritelog (sic!) file. So fix the misnaming and
use constants for mode and open flags.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@100813 13f79535-47bb-0310-9956-ffa450edef68