Show line /char numbers with lint issues

[danpoltawski]

We are checking the wrong condition so line/column numbers were never shown.

I considering switching to _.isNumber, but decided to just try the most minimal fix possible..

Steps to reproduce:

• Use grunt-contrib-csslint on a css file with line errors

Expected results:

• The line number is reported:

[L15:C5]
>> ERROR: Duplicate property 'color' found. Duplicate properties must appear one after the other. (duplicate-properties) Browsers: All

Actual results:

[GENERAL]
>> ERROR: Duplicate property 'color' found. Duplicate properties must appear one after the other. (duplicate-properties) Browsers: All

[vladikoff]

Thanks @danpoltawski !