can't push account keyring to alberti: detected dubious ownership in repository

$ git push alberti
Enumerating objects: 10, done.
Counting objects: 100% (10/10), done.
Delta compression using up to 12 threads
Compressing objects: 100% (7/7), done.
Writing objects: 100% (8/8), 2.89 KiB | 2.89 MiB/s, done.
Total 8 (delta 4), reused 1 (delta 0), pack-reused 0
remote: + env -i HOME=/home/kez make -C /srv/db.torproject.org/keyrings
remote: make: Entering directory '/srv/db.torproject.org/keyrings'
remote: umask 002 && \
remote: 	cd keyring && \
remote: 	git -c safe.directory=/srv/db.torproject.org/keyrings/keyring.git pull && \
remote: 	rm -f torproject-keyring.gpg && \
remote: 	./build-keyring && \
remote: 	cp -f torproject-*.gpg ..
remote: fatal: detected dubious ownership in repository at '/srv/db.torproject.org/keyrings/keyring'
remote: To add an exception for this directory, call:
remote: 
remote: 	git config --global --add safe.directory /srv/db.torproject.org/keyrings/keyring
remote: make: *** [Makefile:5: torproject-keyring.gpg] Error 128
remote: make: Leaving directory '/srv/db.torproject.org/keyrings'
To alberti.torproject.org:/srv/db.torproject.org/keyrings/keyring.git
   598d96a..96a747f  master -> master

so we have dubious ownership in the account-keyring repo on alberti. i think the only solution is to add it as a safe directory, unless we want to require everyone to push to the alberti remote as the git user.

/cc @anarcat @lavamind