Drop compatibility with 1.2 again, properly free the info structure.
Drop compatibility with 1.2 again, properly free the info structure.

Version 1.2 doesn't provide the rrd_info_free function and maintaining
compatibility with 1.2 isn't worth re-implementing it. I use 1.4 anyway.

marineam/nagcat,marineam/nagcat,marineam/nagcat