Fixes #12132 - [API] Host all parameters should include host parameters

Fixes #12241 - Correct counter_cache deadlock fix

Previous fix had a bug - in `:after_commit` `self.changes` is empty, and the
changes are in `self.previous_changes`. Also this only needs to run on
update.
This commit adds tests to make sure cached_counters continue to work...

fixes #11965 - hostgroup with config group - clone should not run validations more than once

Fixes #11924 - Substitute .scoped by .where(nil) to force return relation

On Rails 4 .scoped is deprecated. Calling .all on the model returns the
equivalent ActiveRecord relation object on Rails 4, but on Rails 3 it
returns an Array right away.

A proper replacement we can use is where(nil) - it's ugly but it returns...

fixes #12109 - removing owner_id presence validation

in rails 4, owner is not populated when creating a join model
(user.roles << role created a UserRole on the background)
in rails 3, this is not a problem, in rails 4, the presence validation
fails because no owner_id exists nor does an owner exist. at that...

fixes #12207 - objects with ancestors should not call ancestors if cached

up until now, ancestry objects always called their ancestors when
linking to the object because to_param called get_title instead of title
(which can be cached)
this caused a LOT of pointless queries, slowed down Hosts#index alot

fixes #11345 - API GET request available_clusters sends empty hash

Fixes #12004, #11999 - Remove reserved words from Environment friendly_id

Restores use of friendly_id, but removes 'new', 'edit' etc from the
reserved words list to ensure they can be used as identifiers.

Reverts the id-name parameterization to purely name, which fixes...

refs #12147 - adding permissions setter to roles

Problem

Calling FactoryGirl.build(:role, :permissions => []) needs a setter
directly on role. Otherwise it fails on Rails 4 with:
ActiveRecord::HasManyThroughNestedAssociationsAreReadonly: Cannot modify...

refs #12147 - adding safety guards to method_missing on compute attributes

There's no need to pass to vm_atts when the method is a setter, also,
there's no need to pass if vm_attrs is blank. Those safety guards are
required in rails4, and compatible with 3.