Fix 'Invalid socket file permissions' error

doc/update/7.2-to-7.3.md

@@ -73,7 +73,7 @@ sudo cp lib/support/init.d/gitlab /etc/init.d/gitlab
     # Enable Redis socket for default Debian / Ubuntu path
     echo 'unixsocket /var/run/redis/redis.sock' | sudo tee -a /etc/redis/redis.conf
     # Be sure redis group can write to the socket.
-    echo 'unixsocketperm 775' | sudo tee -a /etc/redis/redis.conf
+    echo 'unixsocketperm 0775' | sudo tee -a /etc/redis/redis.conf
     # Activate the changes to redis.conf
     sudo service redis-server restart
     # Add git to the redis group