ps-mem: update to build with 2.19
ps-mem: update to build with 2.19

elopio/snappy-playpen,ubuntu/snappy-playpen,ubuntu/snappy-playpen,elopio/snappy-playpen,jamestait/snappy-playpen,elopio/snappy-playpen,jamestait/snappy-playpen,ubuntu/snappy-playpen,jamestait/snappy-playpen,elopio/snappy-playpen,jamestait/snappy-playpen,ubuntu/snappy-playpen