MethodCallParentheses lacks exception for empty blocks

[agrimm]

The following code

def foo
  5.times.map() {}
end

would fall foul of the MethodCallParentheses cop.

Unlike #585 , removing the parentheses would not affect Ruby's ability to parse the code, but if parentheses were removed, programmers may be confused as to whether the {} represents a hash, or a block.

So far, I don't have any good use case scenarios as to why someone should write such code, so I don't know if it's worth fixing, but I wanted to let you know.

[bbatsov]

I, too, cannot think of any scenario in which one would be willing to write code like this, so I'll probably leave the code as-is.