Only use gd storage if gd stack has been started up

Add flag to detect if gd stack has started up.

Upon init btif reads from config file:
1. Local adapter name
2. Discovery timeout

And writes:
1. LE keys (x4)
2. Scan default settings
3. Discovery timeout

Test: System boots without failure
Bug: 147315979

Change-Id: I52c24433bc49466bafcc948963041fcd098d9981