just merge from master#2

Merged

simonJi2018 merged 2 commits intosimonJi2018:masterfrom

sonic-net:master

Apr 10, 2018

Commits on Apr 9, 2018

[cfggen]: ignore acl when its type is not defined (#1568)
lguohan
authored

Commits on Apr 10, 2018

[installer]: Umount before delete partition (#1575)

qiluo-msft
authored and
lguohan
committed