Fix watched items in plugins after updating Kodi

[AkariDN]

Closes jdf76/plugin.video.youtube#487

Description

Old Kodi versions incorrectly save path for plugin items in video database (CVideoDatabase::SplitPath() and URIUtils::GetParentPath() behavior mismatch for plugin URLs). This is fixed in 18a2, but when updating video database we have to set new pathes for old plugin items to save watched/progress history in plugins with complex URLs.

How Has This Been Tested?

• Install Kodi 17 and YouTube plugin
• Mark some youtube videos as watched, save resume points
• Update to Kodi 18 with this PR
• Check status of watched youtube videos

Types of change

• Bug fix (non-breaking change which fixes an issue)
• Clean up (non-breaking change which removes non-working, unmaintained functionality)
• Improvement (non-breaking change which improves existing functionality)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that will cause existing functionality to change)
• Cosmetic change (non-breaking change that doesn't touch code)
• None of the above (please explain below)

Checklist:

• My code follows the Code Guidelines of this project
• My change requires a change to the documentation, either Doxygen or wiki
• I have updated the documentation accordingly
• I have read the Contributing document
• I have added tests to cover my change
• All new and existing tests passed

[yol]

Thanks for looking into this. Unfortunately, I don't think we can merge this as-is (see comment).

[AkariDN]

@pkerling done

[yol]

Looking good now, thanks!

Two minors, then I think we are good to go (@MartijnKaijser should probably go into v18):

• Change the version to 113
• Add a comment to the code explaining what this update does and why it is necessary.

[AkariDN]

Done. Please merge this PR before v18 release otherwise we can get more "watch history gone..." tickets.

[MartijnKaijser]

If all good please merge

[yol]

I took the liberty of editing the comment to save some back-and-forth and so you can see what I would expect. Very briefly, the comment should provide enough context to understand why the update is necessary (most other migrations just add columns, it's obvious in that case). Merging this now, thanks for taking care. It will for sure save us some bug reports :-)