Fix gemspec for missing and incorrect requirement

- json is only used for tests
- rails is used in ./lib/remote_user_auth_engine.rb
- openshift-origin-common in ./config/initializers/openshift-origin-auth-remote-user.rb
Merge pull request #1858 from mscherer/fix/gem_spec/auth_remote

Merged by openshift-bot
Update outdated links in 'cartridges' directory.

Addresses Bug 928675
Merge pull request #2181 from BanzaiMan/dev/hasari/bz928675

Merged by openshift-bot