Use generated key instead of hardcoded

Use mongodb key which generate and upload by Astute

Path: /var/lib/astute/mongodb/mongodb.key
Destination: /etc/mongodb.key

Change-Id: Ib710e26ba3c5a1eb63e1cc1dcc4216da0b213626
Closes-Bug: #1314200
Merge "Use generated key instead of hardcoded"