Add try/except for timesync in cold_restart_nodes
Add try/except for timesync in cold_restart_nodes

Do not fail test if time synchronization fails after
node hard reset and just print warning message.

Change-Id: I1e5084476b1006a08e3a2dfd512cd108338f9f5d
Closes-bug: #1365446

ddepaoli3/fuel-main-dev,eayunstack/fuel-main,AnselZhangGit/fuel-main,dancn/fuel-main-dev,teselkin/fuel-main,SmartInfrastructures/fuel-main-dev,zhaochao/fuel-main,stackforge/fuel-main,Fiware/ops.Fuel-main-dev,SergK/fuel-main,dancn/fuel-main-dev,zhaochao/fuel-main,zhaochao/fuel-main,AnselZhangGit/fuel-main,ddepaoli3/fuel-main-dev,dancn/fuel-main-dev,teselkin/fuel-main,Fiware/ops.Fuel-main-dev,AnselZhangGit/fuel-main,Fiware/ops.Fuel-main-dev,zhaochao/fuel-main,ddepaoli3/fuel-main-dev,huntxu/fuel-main,huntxu/fuel-main,teselkin/fuel-main,AnselZhangGit/fuel-main,SergK/fuel-main,SergK/fuel-main,ddepaoli3/fuel-main-dev,zhaochao/fuel-main,huntxu/fuel-main,eayunstack/fuel-main,SmartInfrastructures/fuel-main-dev,stackforge/fuel-main,SmartInfrastructures/fuel-main-dev,Fiware/ops.Fuel-main-dev,teselkin/fuel-main,eayunstack/fuel-main,dancn/fuel-main-dev,SmartInfrastructures/fuel-main-dev,stackforge/fuel-main