Small fixes in templates mongod.conf.erb and init.pp

Hello,

I'm been using your puppet module and I've found two possible bugs that I've fixed.

1. Minor fixes in mongod.conf.erb file:
There was incorrect syntax with assignment of value to dbpath variable
@mongosource variable was not used anywhere and I've changed @mongosource to @source according to the standard used across all .erb file

2. I've had an issue with using current state of init.pp which pointed to the mongod.conf instead of standard mongodb.conf. What happened is that all attributes that I've set are placed in mongod.conf which was not used on nodes where I've installed mongodb with this puppet module .
For example: I wanted to enforce master/slave replication but all data needed for this: master=true, slave=true and source=MASTER_HOST_ADDRESS were entered into the mongod.conf which was not read when started mongo.