Sync oslo imageutils, strutils to Nova

Changes in imageutils:
===============================
b455fac Enable decimal value input in imageutils.QemuImgInfo
bec3a5e Implements SI/IEC unit system conversion to bytes
8b2b0b7 Use hacking import_exceptions for gettextutils._
aad179d Fixing misspelled encryption key in QemuImgInfo
12bcdb7 Remove vim header
2bd46eb Refactors byte size extraction logic

Changes in strutils:
====================
bec3a5e Implements SI/IEC unit system conversion to bytes
e53fe85 strutils bool_from_string, allow specified default
8b2b0b7 Use hacking import_exceptions for gettextutils._
84d461e Fix a bug in safe_encode where it returns a bytes object in py3
12bcdb7 Remove vim header
3970d46 Fix typos in oslo
1a2df89 Enable H302 hacking check
67bd769 python3: Fix traceback while running python3.
b0c51ec Refactors to_bytes

Change-Id: I3e887756af37823dc6486d1496222825ddc20f0c
Related-bug: #1189635
Related-bug: #1193765
Related-Bug: #1257829
Make example 'entry_points' parameter a dictionary

Change-Id: Idad5a1b2d6aaee456cdc3a52554c1d7ddd51a696
Fix straggling uses of direct-to-database queries in nova-network

There were a few remaining calls directly to the database module
left in nova-network. These would fail because of the wedge we
put in place specifically to catch this case. However, we don't
test VlanManager in the gate, which means we didn't catch them
until now.

This required adding two more methods, one each to Network and
NetworkList, but they are both extremely simple.

Change-Id: Iecc382074f060da1bd6f740d7bde0b20a0be2fcf
Closes-bug: #1304724
Merge "Make example 'entry_points' parameter a dictionary"
Merge "Fix straggling uses of direct-to-database queries in nova-network"
Merge "Sync oslo imageutils, strutils to Nova"