Fix EmptyLinesAroundBody so it doesn't report blank lines.

That is, lines with only space. The TrailingSpace cop must do its job first. Then we can deal with the extra empty line in EmptyLinesAroundBody. Otherwise auto-correction doesn't work.
Merge pull request #748 from jonas054/fix_empty_lines_around_body

Fix EmptyLinesAroundBody so it doesn't report blank lines.