Refs #3809 - Remove rubocop TODOs

Removed the following TODOs so that cops for these will run from now on:

Lint/AmbiguousOperator, DefEndAlignment, DeprecatedClassMethods
EnsureReturn, RequireParentheses, Void, BlockAlignment, EndAlignment,
UselessAccessModifier,

Style/IndentArray, IndentHash, Tab, UnlessElse, UnneededPercentQ, UnneededPercentX, RedundantReturn

Rails/Validation
why the extra begin? is it to avoid the ensure ?