Fixes compile issue on FreeBSD/clang

lib/Basics/logging.cpp:1876:12: error: cannot initialize a variable of type 'CODE *' (aka '_code *') with an lvalue of type 'const CODE [25]'
    CODE * ptr = TRI_facilitynames;
           ^     ~~~~~~~~~~~~~~~~~

FreeBSD clang version 3.4.1 (tags/RELEASE_34/dot1-final 208032) 20140512
Target: x86_64-unknown-freebsd10.1