Description of problem:
Nautilus 3.9.92 does not honor mime type specific icons, in the past nautilus could display an icon for an specific mime type file, if the icon exist in the mimetypes folder of the current icon theme and uses the pattern gnome-mime-[mime type name], rigth now it only shows the generic ones.
This affect custom icon themes, and applications like LibreOffice whom install specific mime type icons in the hicolor theme, in this regard for example the LibreOffice icon gnome-mime-application-vnd.oasis.opendocument.text.png is not displayed in nautilus when you look for an odt file (Obviously for this example, you only going to notice this if you turn off the thumbnail generator from LibreOffice for this mime type).

Version-Release number of selected component (if applicable):
3.9.92

How reproducible:
Look for a file that have an specific mimetype icon in your current icon theme or in hicolor fallback theme.

Actual results:
Is displayed the generic icon for that mime type file.

Expected results:
Like older versions of nautilus, display the specific icon for that mime type

Additional info:
It is possible to do manually the association using something like this:
# xdg-icon-resource install --context mimetypes --size 48 myicon-file-type.png x-application-mytype