I get a NaN for inflation if I don't have minting turned on

[njmurarka]

Describe the bug
If I do not have minting turned on in my genesis.json file for my chain, inflation shows as NaN in the BigDipper app.

To Reproduce
Steps to reproduce the behavior:
Turn off inflation and start the chain
Observe the inflation display

Expected behavior
Inflation should be 0 or just not show

Screenshots
See screenshot

[kwunyeung]

Yeah, we didn't handle that properly. Thanks for creating this issue. We are going to remove reading genesis file and move all parameters reading on chain on the fly.

[kwunyeung]

Tracked in #429