Explicitly set /bin/bash for running innobackupex-restore-call.sh script

Salt command using /bin/sh shebang if it's not specified clearly.
While innobackupex-restore-call.sh script supports only /bin/bash.

Change-Id: Iee6f351b6907e3ea601799679c4ee148aad86a5d
Related-Prod: PROD-32439
diff --git a/xtrabackup/client/restore.sls b/xtrabackup/client/restore.sls
index d6780e1..f9fd843 100644
--- a/xtrabackup/client/restore.sls
+++ b/xtrabackup/client/restore.sls
@@ -17,7 +17,7 @@
 
 xtrabackup_run_restore:
   cmd.run:
-  - name: /usr/local/bin/innobackupex-restore-call.sh
+  - name: /bin/bash /usr/local/bin/innobackupex-restore-call.sh
   - user: root
   - unless: "[ -e {{ client.backup_dir }}/dbrestored ]"
   - require: