inveniocfg: fix for mod_headers

Reviewed-by: Tibor Simko <tibor.simko@cern.ch>
Merge branch 'maint-1.1'

* maint-1.1:
  inveniocfg: fix for mod_headers
Merge branch 'master' into next

* master:
  inveniocfg: fix for mod_headers

Conflicts:
	modules/miscutil/lib/inveniocfg.py

Signed-off-by: Tibor Simko <tibor.simko@cern.ch>