rbconfig not accurate on ruby version

Author: nateberkopec

lib/raven/context.rb

@@ -34,7 +34,7 @@ def os_context
       def runtime_context
         @runtime_context ||= {
           "name" => RbConfig::CONFIG["ruby_install_name"],
-          "version" => RbConfig::CONFIG["ruby_version"]
+          "version" => Raven.sys_command("ruby -v")
         }
       end
     end

spec/raven/event_spec.rb

@@ -67,7 +67,7 @@
     end
 
     it 'has runtime' do
-      expect(hash[:contexts][:runtime]["version"]).to eq(RbConfig::CONFIG["ruby_version"])
+      expect(hash[:contexts][:runtime]["version"]).to eq(`ruby -v`)
     end
   end