Nemo inactive pane improvement

Fixes the problem of icons in the inactive pane not correctly displayed background-selection colors:

OLD:
![](http://i.imgur.com/nT44KV0.png)

NEW:
![](http://i.imgur.com/Fo8xba5.png)

Proviso: this working depends on the application-priority background-color setting that is included in Nemo itself being unset, otherwise Nemo will override the theme setting. Worst case it will do nothing without the right build.