Sync safe changes from oslo-incubator

Sync a bunch of changes from oslo-incubator that are either obviously
safe, add new code that ironic doesn't use or modifies existing code
that ironic doesn't use.

The commits are:

  fe2f108 Enable hacking H702 localization test
  0a14e1d Enable hacking H703: Multiple positional placeholders
  a4a6789 Pass backdoor_port to services being launched
  d5e57e9 Add DynamicLoopCall timers to ThreadGroups
  926b3e9 Fixes import order nits
  a514693 Removes len() on empty sequence evaluation
  ab6b2d4 Line wrapper becomes to long when expanded.
  b873454 Added convenience APIs for lockutils
  562cc68 Stylistic improvements from quantum-rootwrap
  3893ef8 Import trycmd and ssh_execute from nova.

Change-Id: I0a900b35e4bb4ddd56ecc083a30b0b1fba2e8b04
Merge "Sync safe changes from oslo-incubator"