Fixed the incorrect Git URL in the `rake setup` task
[EXT] Removed the dependency on the "backup" gem

The `bundle install` command was failing on Ruby 1.8.7 because of:

    Gem::InstallError: httparty requires Ruby version >= 1.9.3.
    An error occurred while installing httparty (0.12.0), and Bundler cannot
    continue.

Mocked out the Backup gem's modules and class in the unit test.
[EXT] Added more defensive code in the `Test::Cluster#__print_cluster_info` method

Constantly failing on Jenkins...

https://build-eu-1.elasticsearch.org/job/es-ruby_core/ES_V=1.3_nightly,RUBY_V=1.9.3-p448,TEST_TYPE=integration,jdk=JDK7,label=metal-pool/lastBuild/console
Release EXT:0.0.17
Merge branch 'master' into fix/missing-rake-in-tasks