Instructions if someone else get similar situation on Ubuntu 16.04 :
sudo apt-get purge apparmor
sudo apt-get purge apparmor-profiles
sudo apt-get purge apparmor-utils
sudo apt-get remove snapd snapd-confine
Now Install back them all:
sudo apt-get install apparmor-utils
sudo apt install apparmor-profiles apparmor-profiles-extra vim-addon-manager
sudo apt install snapd snapd-login-service snap-confine
Reboot System and test with
sudo apparmor_status
You will see apparmor profiles are now loaded and snap install command also working
sudo snap install hello-world