Fix incorrect int/tuple comparison during binary search

The code contains an incorrect int/tuple comparison during the binary
search, which completely breaks the "priority" feature.
(Apparently python2 thinks int < tuple is not an error and always True.)

Change-Id: Ic404b38eabc87b105c7c2443b6177071b26d97ce
Closes-Bug: #1386946
Migrate to oslo.utils

The following modules are removed:
  - excutils,
  - importutils,
  - network_utils,
  - strutils,
  - timeutils.

Closes-Bug: #1385355
Change-Id: I1f34f17f5dbf37032584008f27e65d4dc4d475f4
Merge "Fix incorrect int/tuple comparison during binary search"
Merge "Migrate to oslo.utils"