[Incubator/mysqlha] rechedule fails with persistent disks (#5523)

* STOP SLAVE IO_THREAD before changing master in xtrabackup container

* Remove slave existing data before cloning

* incremented chart version

* fix typo

incubator/mysqlha/Chart.yaml

@@ -1,5 +1,5 @@
 name: mysqlha
-version: 0.2.0
+version: 0.2.1
 appVersion: 5.7.13
 description: MySQL cluster with a single master and zero or more slave replicas
 keywords:

incubator/mysqlha/templates/statefulset.yaml

@@ -23,12 +23,14 @@ spec:
           - "-c"
           - |
             set -ex
-            # Skip the clone if data already exists.
-            [[ -d /var/lib/mysql/mysql ]] && exit 0
             # Skip the clone on master (ordinal index 0).
             [[ `hostname` =~ -([0-9]+)$ ]] || exit 1
             ordinal=${BASH_REMATCH[1]}
             [[ $ordinal -eq 0 ]] && exit 0
+
+            # If data already exists, delete and proceed to clone.
+            [[ -d /var/lib/mysql/mysql ]] && rm -fr /var/lib/mysql/*
+
             # Clone data from previous peer.
             ncat --recv-only {{ template "fullname" . }}-$(($ordinal-1)).{{ template "fullname" . }} 3307 | xbstream -x -C /var/lib/mysql
             # Prepare the backup.
@@ -191,6 +193,7 @@ spec:
             # In case of container restart, attempt this at-most-once.
             cp change_master_to.sql.in change_master_to.sql.orig
             mysql -h 127.0.0.1 --verbose<<EOF
+            STOP SLAVE IO_THREAD;
             $(<change_master_to.sql.orig),
             MASTER_HOST='{{ template "fullname" . }}-0.{{ template "fullname" . }}',
             MASTER_USER='${MYSQL_REPLICATION_USER}',