percona_show_slave_status_nolock leaves slave server DEBUG_SYNC set

[Laurynas Biveinis]

Bug 1617323 fix is incomplete, PS 5.5 trunk:

main.percona_show_slave_status_nolock [ pass ] 3029

MTR's internal check of the test case 'main.percona_show_slave_status_nolock' failed.
This means that the test case does not preserve the state that existed
before the test case was executed. Most likely the test case did not
do a proper clean-up. It could also be caused by the previous test run
by this thread, if the server wasn't restarted.
This is the diff of the states of the servers before and after the
test case was executed:
mysqltest: Logging to '/Users/laurynas/percona/obj-testcase-check-exp-5.5-debug-asan/mysql-test/var/tmp/check-mysqld_2.log'.
mysqltest: Results saved in '/Users/laurynas/percona/obj-testcase-check-exp-5.5-debug-asan/mysql-test/var/tmp/check-mysqld_2.result'.
mysqltest: Connecting to server localhost:13002 (socket /Users/laurynas/percona/obj-testcase-check-exp-5.5-debug-asan/mysql-test/var/tmp/mysqld.2.sock) as 'root', connection 'default', attempt 0 ...
mysqltest: ... Connected.
mysqltest: Start processing test commands from './include/check-testcase.test' ...
mysqltest: ... Done processing test commands.
--- /Users/laurynas/percona/obj-testcase-check-exp-5.5-debug-asan/mysql-test/var/tmp/check-mysqld_2.result 2016-08-31 09:53:47.000000000 +0300
+++ /Users/laurynas/percona/obj-testcase-check-exp-5.5-debug-asan/mysql-test/var/tmp/check-mysqld_2.reject 2016-08-31 09:53:51.000000000 +0300
@@ -445,7 +445,7 @@
 VERSION_COMPILE_OS osx10.11
 WAIT_TIMEOUT 28800
 VARIABLE_NAME VARIABLE_VALUE
-DEBUG_SYNC ON - current signal: ''
+DEBUG_SYNC ON - current signal: 'signal.after_show_slave_status'
 CATALOG_NAME SCHEMA_NAME DEFAULT_CHARACTER_SET_NAME DEFAULT_COLLATION_NAME SQL_PATH
 def information_schema utf8 utf8_general_ci NULL
 def mtr latin1 latin1_swedish_ci NULL

mysqltest: Result content mismatch

[Laurynas Biveinis (laurynas-biveinis)]

     https://github.com/percona/percona-server/pull/953
     https://github.com/percona/percona-server/pull/954

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PS-3543