Please note that updating using git is not officially supported, but I wouldn't expect anything to be able to go wrong there.
Also note that 10.0.5 was qualified a broken release. Please check out v10.0.6, run make and try again. See https://central.owncloud.org/t/owncloud-server-10-0-5/11543
Did you see any errors during the occ upgrade command ? Please check the oc_accounts table to see if your user still properly exists.
What version did you have before ? (also a question from the issue template I posted)