make CI config more robust to network about ocrd_all

[kba]

Tough to do something sensible about something so unpredictable. Maybe something like make foo || (sleep 60;echo "Failed once, waiting 60 seconds, trying again"; make foo) to just repeat steps? Ugly as hell but if the network is just gone for more then a few seconds it might help.

[kba]

I restarted the build. @stweil @bertsky Do you have the rights to do that yourself at https://circleci.com/gh/OCR-D/workflows/ocrd_all ?

[stweil]

I don't have the rights.

[bertsky]

fixed as of #77