Removed eth0 from MongoDB bind address

The bind address specified for MongoDB was hardcoded to eth0.
This broke deployments which use different interface for default
interface.  Updated the configuration to use address of default
interface.

Change-Id: Ic87e9d0e9d668235ff463ccb26548e54ec28633d
Closes-Bug: #1287306
Merge "Removed eth0 from MongoDB bind address"