[yocto] Yocto Project Source Mirroring - Now working correctly

[Richard Purdie]

Hi,

At ELC-E/OEDEM there were reports of problems with the project's source
mirroring. We've also had reports of problems with people using http
only connections without access to git (e.g. being behind http only
proxies).

Michael and I have looked into it and there were some problems caused
by the new autobuilder changes and switches between NAS systems on that
infrastructure. Those are now resolved and all data has been updated.
The git mirroring issues were also resolved by tweaking some of the
mirroring commands.

In order to stop this regressing again without us noticing, I've also
written an oe-selftest which will ensure this continue to work as
intended and alert us if it doesn't.

If anyone does see any further oddities, please let Michael and myself
know.

Cheers,

Richard