We were upgrading from 10.1.14 to 10.1.16.
The script /usr/bin/galera_recovery does not behave correctly when an error log is defined in my.cnf.
systemd error log showed during upgrade :
WSREP: Failed to recover position: '2016-07-19 9:46:23 140555529492416 [Note] /usr/sbin/mysqld (mysqld 10.1.16-MariaDB-1~jessie) starting as process 111710 ...'
Using the patch attached, this solve our issue.