In the newest commit of puppetlabs-mongodb, we have to specify which
version or which service_name we run for MongoDB service.
On Debian Wheezy, it's still MongoDB 2.4 so the service_name is
'mongodb'.
For more details about that change, look at this commit:
5e229857c29bd44c9d812a21bed69098bf670a6a
It requires to hardcode the verison of the package we use.
On both RH & Debian, we use 2.4 for now.
Change-Id: Ib29cadfe5be3fff64b513cb07b9d18b27dd8ade9
56007364a2