Don't use Ember.Error for needsFinallyFix.

As mentioned in
https://github.com/emberjs/ember.js/pull/3594/files#r7088644 this does
not need to use `Ember.Error`.
[DOC] Use proper versioning string.

[ci skip]
reduce computed @self -> @this
Merge pull request #3620 from rjackson/fixup_ember_error_usage

Don't use Ember.Error for needsFinallyFix.
Merge pull request #3622 from rjackson/use_placeholder_version_string_in_yuidoc

[DOC] Use proper versioning string.
Merge pull request #3624 from emberjs/self_to_this

reduce computed @self -> @this