Werk #6047: docker_node_info: Fix crash in case docker process is not running

ComponentHW/SW-Inventory
Titledocker_node_info: Fix crash in case docker process is not running
Date2018-04-29 19:51:37
Check_MK EditionCheck_MK Raw Edition (CRE)
Check_MK Version1.6.0i1,1.5.0b3
LevelTrivial Change
ClassBug Fix
CompatibilityCompatible - no manual interaction needed