Allow display_name for v2 snapshot-update

According to the comment in the source code, the snapshot-update of
v2 would be able to allow either "name" or "display_name" parameter.
And if both paramters are specified, "name" parameter is effective
over "display_name" like "description" parameter.
However "display_name" parameter is ignored now, because cinder writes
over empty dict(update_dict['display_name']).

This patch fixes the problem.

Fixes bug #1226398

Change-Id: Icd48556a26b9346f73b7c1b82ffbcdd469c4d28d
Fix secure delete for thick LVM snapshots

This change modifies the behaviour of the secure delete for thick
LVM snapshots to wipe the underlying COW of the snapshot LV
instead of the snapshot LV itself.

This change is necessary because the snapshot LV does not contain
exactly the same number of writable blocks as the original LV.  The
COW includes header information per COW block that identifies the
device as a COW device as well as the source and destination blocks
for the changed item.  The amount of metadata contained in the COW is
variable based on I/O performed on the snapshot.

This does not change the behavior of secure deletes on thin LVs
or secure deletes on the thick LV snapshot origin.

Closes-Bug: #1191812
Change-Id: I20e02b6c20d5ac539b5b5469e665fc986180f2e9
Merge "Fix secure delete for thick LVM snapshots"
Fixes call GlanceConnectionFailed in invalid ARG

A mapping key of 'netloc' is always ignored. Thus information in
'netloc' is lost. But because it is included in 'error_msg', I remove
'netloc=netloc'.

Change-Id: I937044bcca0cb196fcd96cfa421de777713d76f5
Closes-Bug: #1226959
Merge "Allow display_name for v2 snapshot-update"
Merge "Fixes call GlanceConnectionFailed in invalid ARG"