Fix MongoDB setup on nonha setup

Fix MongoDB setup on nonha setup

Currently a replset parameter is set in mongodb.conf no matter if we are
in a ha or nonha setup. This install fine, but on a nonha setup it prevents
any program from using MongoDB, since no replset has been initialized. It
generates the following error when a program tries to use it :

not master and slaveOk=false

To prevent this issue a replicatset is initialized in both ha and nonha
setup, this way if another MongoDB node is added to the pool, it will be
able to attach automatically

Change-Id: I65e3f1ad35cb0cd31f6771444a0cffdf7569222f