opus: broken tag reader with .ogg file extension

Before posting

Please follow the steps below and check the boxes with [x] once you did the step.

[x] I checked the issue tracker for similar issues
[x] I checked the changelog if the issue is already resolved
[x] I tried the latest Clementine build from here

System information

Please provide information about your system and the version of Clementine used.

Operating Systems: Windows 10 x64, Arch Linux x64
Clementine versions: 1.3.1, 1.3.1-318-ge3ece3d, 1.3.1-322-ga5d12d0

libgstopus and libopus are installed.

Expected behaviour / actual behaviour

expected behaviour: Clementine adds ogg/opus files with .ogg file extension to the music library and tag reader reads the opus tags.

actual behaviour: Clementine's music library and tag reader doesn't support ogg/opus files with .ogg file extension. Music library and tag reader only work with .opus file extension.

The Xiph.Org Foundation defines .opus as the recommended file extension for ogg/opus files, but it should work with .ogg file extension, too.

I checked the ogg/opus file for a valid ogg container, looks fine and the tags are in the file. The file was created by opusenc --bitrate 128 --vbr --title "title" --artist "artist" --album "albumtitle" --date "2016" --genre "genre" source.wav dest.ogg from a wav file.

Steps to reproduce the problem (only for bugs)

Put a ogg/opus file with .ogg file extension in a folder which is added to the music library.

clementine-player / Clementine