Add SSL debugging

Previously there was no good way to view the SSL configuration that
was eventually negotiated.  This change ensures that that information
is logged at DEBUG.

Author: nebhale

java-buildpack.iml

@@ -274,7 +274,7 @@
     <orderEntry type="library" scope="PROVIDED" name="addressable (v2.3.6, rbenv: 1.9.3-p547) [gem]" level="application" />
     <orderEntry type="library" scope="PROVIDED" name="ast (v2.0.0, rbenv: 1.9.3-p547) [gem]" level="application" />
     <orderEntry type="library" scope="PROVIDED" name="astrolabe (v1.3.0, rbenv: 1.9.3-p547) [gem]" level="application" />
-    <orderEntry type="library" scope="PROVIDED" name="bundler (v1.7.3, rbenv: 1.9.3-p547) [gem]" level="application" />
+    <orderEntry type="library" scope="PROVIDED" name="bundler (v1.7.4, rbenv: 1.9.3-p547) [gem]" level="application" />
     <orderEntry type="library" scope="PROVIDED" name="codeclimate-test-reporter (v0.4.1, rbenv: 1.9.3-p547) [gem]" level="application" />
     <orderEntry type="library" scope="PROVIDED" name="crack (v0.4.2, rbenv: 1.9.3-p547) [gem]" level="application" />
     <orderEntry type="library" scope="PROVIDED" name="debugger-ruby_core_source (v1.3.5, rbenv: 1.9.3-p547) [gem]" level="application" />

lib/java_buildpack/util/cache/download_cache.rb

@@ -256,6 +256,7 @@ def secure?(uri)
         def update(uri, cached_file)
           proxy(uri).start(uri.host, uri.port, http_options(uri)) do |http|
             @logger.debug { "HTTP: #{http.address}, #{http.port}, #{http_options(uri)}" }
+            @logger.debug { http.instance_variable_get('@socket').io.session.to_text } if secure? uri
             request = request uri, cached_file
             request.basic_auth uri.user, uri.password if uri.user && uri.password