Core: Do not overide log file when running as a daemon

The -L/--log option is ignored when you run Deltacloud
in 'daemon' mode (-d). This cause Deltacloud to log into
syslog even user specify the log file location explicately.
Core: Updated gemspec to include migrations and db-upgrade command
Core: Raise error if the collection is already registred in Rabbit

This patch will make sure you don't have two duplicate collections
registred to Rabbit both for DC and CIMI.
Core: Fix code duplication in how we load collections

This patch introduce new helper that provide mechanism
to load all collection for the given frontend
Core: Fix for rake cimi:routes

Since we now have initializers, we not longer need to load
config.ru to have all stuff initialized.