Allow sharding when there are hidden secondaries.

MongoDB's addShard command fails if the connection string includes
hidden members. See <https://jira.mongodb.org/browse/SERVER-9882>.

Omit hidden members from connection strings to work around this
problem.
Merge pull request #162 from mkantor/fix-sharding-with-hidden-secondaries

Fix sharding with hidden secondaries.
no berks lerks
Update gemfile.lock for new tk and berkshelf
remove Gemfile.lock, update Gemfile to 'stable'
add debian stable for kitchen, split default and 10gen
v0.13.6
remove Gemfile.lock