encryption.innodb-discard-import failed in buildbot with timeout

encryption.innodb-discard-import '4k,ctr,innodb' w2 [ fail ]  timeout after 900 seconds

        Test ended at 2019-03-23 01:08:00

Test case timeout after 900 seconds

== /dev/shm/var/2/log/innodb-discard-import.log == 

t1.ibd

t2.cfg

t2.frm

t2.ibd

t3.cfg

t3.frm

t3.ibd

t4.cfg

t4.frm

t4.ibd

UNLOCK TABLES;

ALTER TABLE t1 DISCARD TABLESPACE;

ALTER TABLE t2 DISCARD TABLESPACE;

ALTER TABLE t3 DISCARD TABLESPACE;

ALTER TABLE t4 DISCARD TABLESPACE;

restore: t1 .ibd and .cfg files

restore: t2 .ibd and .cfg files

restore: t3 .ibd and .cfg files

restore: t4 .ibd and .cfg files

ALTER TABLE t1 IMPORT TABLESPACE;

 == /dev/shm/var/2/tmp/analyze-timeout-mysqld.1.err ==