rule one-var fix to incorrect code when using semicolon-less style

[aladdin-add]

Tell us about your environment

• ESLint Version: master
• Node Version: n
• npm Version: n

What parser (default, Babel-ESLint, etc.) are you using?
default
Please show your full configuration:

{
  "one-var": 2
}

What did you do? Please include the actual source code causing the issue, as well as the command that you used to run ESLint.

var i
var j

What did you expect to happen?
it should be fixed to

var i, j

What actually happened? Please include the actual, raw output from ESLint.

var ,
 j

[malcolmsgroves]

I'll work up a PR for this