defaultLang not used

[nleush]

When switch to not supported language - default language from plugin.json not used.

[julianlam]

Likely resolved as per NodeBB/NodeBB#3963, thanks!

[nleush]

Still have:

error: [translator] Could not load `iframely`: ENOENT, open '...public/language/de/iframely.json'. Skipping...

on current 'master' version.