Bugs in gLogger usage

These were fixed in later versions (v6r12 for one, integration the other)
instances does not exist, only step_instances
setParents does not exist, only setParent
Protect against missing MetaData, e.g. GUID empty string
PRODUCTION_ID and JOB_ID are taken from workflow_commons (cf. test_modules wf_commons)
Merge pull request #2203 from andresailer/SomeFixes

[v6r11] Some fixes