Changing the path of the jQuery theme to "smoothness"

Changing the path of the jQuery theme to "smoothness", since "base" is not in the bundle.

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | ---
| Refs tickets  | https://github.com/zikula/core/pull/1826
| License       | MIT
| Doc PR        | ---