src/pmie/src/systemlog.c: be more careful about the const qualifier
src/pmie/src/systemlog.c: be more careful about the const qualifier

The decode() procedure is called with a codetab argument ... in the
calls this is facilitynames[] or prioritynames[] both of which are
const arrays .. so make the definition of codetab const also.

Found by the FreeBSD 10.2 C compiler.

aeg-aeg/pcpfans,aeg-aeg/pcpfans,wuliming/pcp,wuliming/pcp,aeg-aeg/pcpfans,wuliming/pcp,wuliming/pcp,adfernandes/pcp,adfernandes/pcp,aeg-aeg/pcpfans,wuliming/pcp,aeg-aeg/pcpfans,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,wuliming/pcp,wuliming/pcp,wuliming/pcp,adfernandes/pcp,aeg-aeg/pcpfans,adfernandes/pcp,adfernandes/pcp,aeg-aeg/pcpfans,aeg-aeg/pcpfans