Test debug_key_management fails sporadically in buildbot.

Problem is that we expect key_version to be increasing so
before we reset debug_key_management plugin key_version
disable encryption.

mysql-test/suite/encryption/r/debug_key_management.result

+set global innodb_encrypt_tables=ON;
 show variables like 'innodb_encrypt%';
 Variable_name	Value
 innodb_encrypt_log	ON
@@ -16,4 +17,5 @@ space	name	current_key_version
 0	NULL	10
 1	mysql/innodb_table_stats	10
 2	mysql/innodb_index_stats	10
+set global innodb_encrypt_tables=OFF;
 set global debug_key_management_version=1;

mysql-test/suite/encryption/t/debug_key_management.opt

---innodb-encrypt-tables=ON
 --innodb-encrypt-log=ON
 --innodb-encryption-rotate-key-age=2
 --innodb-encryption-threads=4

mysql-test/suite/encryption/t/debug_key_management.test

@@ -5,6 +5,7 @@ if (`select count(*) = 0 from information_schema.plugins
   --skip Needs debug_key_management
 }
 
+set global innodb_encrypt_tables=ON;
 show variables like 'innodb_encrypt%';
 
 let $wait_condition= select count(*) = 3 from information_schema.innodb_tablespaces_encryption where current_key_version=1;
@@ -17,5 +18,7 @@ let $wait_condition= select count(*) = 3 from information_schema.innodb_tablespa
 --source include/wait_condition.inc
 
 select space,name,current_key_version from information_schema.innodb_tablespaces_encryption order by space;
+# Note that we expect that key_version is increasing so disable encryption before reset
+set global innodb_encrypt_tables=OFF;
 set global debug_key_management_version=1;