Update oslo-incubator loopingcall module

Changes -
 * Use hacking import_exceptions for gettextutils._

Change-Id: I45fc618a09022ebcc351328be2e2f83693d05f2f
Update oslo-incubator processutils module

Changes -
 * Use hacking import_exceptions for gettextutils._

Change-Id: I61c23a3113965341293e006da9e7eba5d865969c
Node group handling improved in the db module

Node groups 'None' value is now treated as an empty list.

Change-Id: Ifef411f0548b150afdc06dd1eb699471f8aa8d1b
Merge "Update oslo-incubator loopingcall module"
Merge "Update oslo-incubator processutils module"
Merge "Node group handling improved in the db module"