After a DNS lookup failure, assume there is no internet connection.

This can occur in two places. If it occurs when sending a HEAD request
against a version of an item in the application cache, mark the
internet as unavailable and use the cached item. If it occurs when
downloading an item, mark the internet as unavailable and look for the
item in the buildpack cache.

[#66409480]
Merge 66409480-recover-from-dns-lookup-failure to 2.0.x

[Completes #66409480]
Merge branch '2.0.x'
Ruby upgrade

This change upgrades the required Ruby version to 1.9.3-p545.

[#66342314]
Merge 66342314-ruby-upgrade to 1.5.x

[Completes #66342314]
Merge branch '1.5.x' into 2.0.x
Merge branch '2.0.x'

Conflicts:
	.travis.yml
	Gemfile.lock
Dependency updates

This change updates all of the dependencies to their latest versions.
It includes changes to some tests to handle the new version of RSpec.
Test against 2.1.1

Since it would appear likely that Cloud Foundry will be skipping the
2.0 line completely, this change updates the test configuration to
start testing against 2.1.1.
Merge branch 'master' of github.com:cloudfoundry/java-buildpack