mariabackup failed if password is passed via environment variable

+ sudo mysqld_safe --defaults-extra-file=/home/buildbot/node2.cnf --user=mysql

ERROR 2002 (HY000): Can't connect to MySQL server on 'localhost' (111)

+ sleep 3

210401 02:24:22 mysqld_safe Adding '/usr/lib/x86_64-linux-gnu/libjemalloc.so.1' to LD_PRELOAD for mysqld

210401 02:24:22 mysqld_safe Logging to '/var/lib/node2/node2.err'.

210401 02:24:22 mysqld_safe Starting mysqld daemon with databases from /var/lib/node2

+ for i in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

+ mysql -uroot -prootpass --port=8302 --protocol=tcp -e 'select * from mgc.t1'

ERROR 2013 (HY000): Lost connection to MySQL server at 'handshake: reading initial communication packet', system error: 104

+ sleep 3

+ for i in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

+ mysql -uroot -prootpass --port=8302 --protocol=tcp -e 'select * from mgc.t1'

ERROR 2002 (HY000): Can't connect to MySQL server on 'localhost' (111)

+ sleep 3