Fix mysql backup directory creation path for affected nodes

Do not use mktemp -d and create dir explicitly with timestamp in name
without templated names, to have one dir path for all affected node
at the time of retore.

Change-Id: I0f03d0f27a424ccdcaaf95b30209bff7c76e031c
Related-Prod: PROD-34371
diff --git a/src/com/mirantis/mk/Galera.groovy b/src/com/mirantis/mk/Galera.groovy
index e5ffe12..3b6f626 100644
--- a/src/com/mirantis/mk/Galera.groovy
+++ b/src/com/mirantis/mk/Galera.groovy
@@ -378,8 +378,8 @@
 
     if (restoreDb) {
         def timestamp = common.getDatetime()
-        salt.cmdRun(env, lastNodeTarget, "mkdir -p /root/mysql")
-        def bakDir = salt.getReturnValues(salt.cmdRun(env, lastNodeTarget, "mktemp -d --suffix='_${timestamp}' /root/mysql/mysql.bak.XXXXXX", false))
+        def bakDir = "/root/mysql/mysql.bak.${timestamp}".toString()
+        salt.cmdRun(env, lastNodeTarget, "mkdir -p ${bakDir}")
         salt.cmdRun(env, lastNodeTarget, "mv /var/lib/mysql/* ${bakDir} || echo 'Nothing to backup from directory /var/lib/mysql/'")
     }
     if (total) {