unable to read environment variable in shiro.ini

Hello Team,
I am not able to read my password using the environment variable.

I don't want to use a plain text password in shiro.ini
When I am writing variables in interpolation format like 

${pass}

Zeppelin is considering '${pass}' as a string and not a variable.
So instead of picking up the value from the variable, the variable name itself becomes a password.
 

Some other details:
Zeppelin version = 0.8.0 and 0.10.1

shiro.ini looks like

[Users]
admin = ${pass}, admin

ENV

root@myserver:/opt/zeppelin-0.8.0-bin-all# env | grep -i pass
pass=123