switch to using memcached as the default caching backend for dashboard

The local memory cache causes bugs when running multiple apache
processes because each process has its own private cache[1]

https://docs.djangoproject.com/en/1.4/topics/cache/#local-memory-caching

Fixes bnc#829058 - dashboard project randomness
Merge pull request #92 from mapleoin/memcached

switch to memcached as the default caching backend
Add apache2 dependency to cookbook

This worked out by luck so far, but it should really be there.
Add crowbar-status and crowbar-failed in schema

Otherwise, barclamp_mgmt_lib.rb will edit the schema and add them, which
will make the files differ from the ones in the package.

Part of https://bugzilla.novell.com/show_bug.cgi?id=776583
Set proposal_schema_version to 2 in crowbar.yml

This is needed when we have crowbar-status/crowbar-failed in the schema.
Merge pull request #93 from vuntz/apache2-dep

https://github.com/crowbar/barclamp-nova_dashboard/pull/93

Merged by devtool for cloudsleuth
Merge pull request #94 from vuntz/add-missing-attributes

Add crowbar-status and crowbar-failed in schema [7/18]