Add force reconfig of peergrouper

When restoring sometimes we need to re-set peergrouper
even if there is a configuration in place.
Added tests for initiatemongoserver

Added tests for initiatemongoserver, formerly known
as MaybeInitiateMongoServer but now supporting a force
parmeter.
I also added an error that is returned when a replicaset
is found in order to add more transparency.
Merge pull request #1306 from perrito666/restore_02_add_peergrouper_force_initiate

Add force reconfig of peergrouper

When restoring sometimes we need to re-set peergrouper
even if there is a configuration in place.

(Review request: http://reviews.vapour.ws/r/620/)