Fix some compilation warning when MIME_MAGIC_DEBUG is defined.

warning: format ‘%x’ expects argument of type ‘unsigned int’, but argument <n> has type ‘<something> *’ [-Wformat=]

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1805491 13f79535-47bb-0310-9956-ffa450edef68