Css dept-* rules should start with 1 not 0

Fixes an issue introduced with #2203, where the padding for `select2-result-label`'s got set  wrong.

Reproduce:
Goto http://ivaynberg.github.io/select2/select2-latest.html#basics, open the dropdown, you can see the padding is wrong (the list items are indented to much). The current stable version http://ivaynberg.github.io/select2/#basics works fine.

The solution is quite easy, `select2-results-dept-*` has to start with 1.