Issue #93
Change version of nexus to 2.9.2
Merge pull request #94 from atoulme/make_chef_vault_optional

Issue #93
Merge pull request #95 from atoulme/use_nexus_2.9.2

Change version of nexus to 2.9.2
Remove private status to methods in Nexus lib

Those methods are just getters and are useful when we want to access
advanced configuration. For instance, encrypted_data_bag_for can be
used to easily encrypt/decrypt the users list in data bags.
Allow provider configuration in LWRP

You can now use the attribute `repo_provider` for hosted, proxy and
group repositories. This will default to `maven2` but you can use
* `rubygems-hosted`
* `rubygems-group`
* `rubygems-proxy`
* `nuget-proxy`
* ...etc

Fixes #97