Disable scheduled maintenance branch docker builds

 - separate new template for maintenance branches from
   master job template (which remains scheduled)
 - disable maintenance jobs scheduling with empty cron
 - note that this should be only temporary workaround until
   the affected dcaegen2 CSIT setups have been improved
Issue-ID: DMAAP-1502

Signed-off-by: Lasse Kaihlavirta <l.kaihlavirt@partner.samsung.com>
Change-Id: If121a835b2f9f2d7f41c06ebc3dfeb0bc549486c
1 file changed