Fixes 'bundle lock' exception with GemCache source.

The bundle lock command was throwing an exception when processing a
Gemfile like the following.

  source Bundler::Source::GemCache.new("path" => "/tmp")

2 files changed, 11 insertions, 0 deletions

diff --git a/lib/bundler/source.rb b/lib/bundler/source.rb
index cccf031fd1..de9eddea57 100644
--- a/lib/bundler/source.rb
+++ b/lib/bundler/source.rb
@@ -130,7 +130,10 @@ module Bundler
     end
 
     class GemCache
+      attr_reader :options
+
       def initialize(options)
+        @options = options
         @path = options["path"]
       end
 
diff --git a/spec/lock/gems_spec.rb b/spec/lock/gems_spec.rb
index 95e8bdc86a..11cd3f3592 100644
--- a/spec/lock/gems_spec.rb
+++ b/spec/lock/gems_spec.rb
@@ -72,4 +72,12 @@ describe "bundle lock with gems" do
     bundle :install
     out.should =~ /You changed your Gemfile after locking. Please run `bundle install --relock`/
   end
+
+  it "correctly serializes GemCache sources" do
+    gemfile <<-G
+      source Bundler::Source::GemCache.new("path" => "#{tmp}")
+    G
+
+    bundle :lock
+  end
 end