"Drive" backend failure

[cyrillelegrand]

While initing submodules for Delta, I can't clone Harmony:

Cloning into '/Users/clegrand/Desktop/Delta/External/Harmony/External/Roxas'...
fatal: remote error: upload-pack: not our ref c7b27f6ccbcf60ac12765e73c16b39259357269f
fatal: Fetched in submodule path 'External/Harmony/Backends/Drive', but it did not contain c7b27f6ccbcf60ac12765e73c16b39259357269f. Direct fetching of that commit failed.
fatal: Failed to recurse into submodule path 'External/Harmony'

And actually, on this repo, while browsing https://github.com/rileytestut/Harmony/tree/master/Backends
if you click on "Drive @ c7b27f6" the link is broken: https://github.com/rileytestut/Harmony-Drive/tree/c7b27f6ccbcf60ac12765e73c16b39259357269f