NSX plugin: return 400 for invalid gw certificate

Gateway certificates are validated by the NSX backend.
The code currently treats a failure in certification
validation as a backend failure and therefore returns
a 500 status code.

This patch changes this behaviour by returning a 400
status code and an appropriate error description.
To this aim a handler for 400 errors has been added to
the NSX API client.

Closes-Bug: #1293508

Change-Id: I196f14337e47cd40710a6d8a30bbe1cac5ffe05b
Update BigSwitch Name to its correct name

Update Neutron documentation and code comments to replace
"BigSwitch" name to "Big Switch"

Closes-Bug: #1299145
Change-Id: I7c14f6170871b361c8929898ee6af5d1a1f41714
Only send notifications on uuid device_id's

Neutron assumes that all ports with the device_owner that start with
'compute:' are ports created by nova compute. Thus, when the debug agent
creates a port with device_owner = compute:probe the nova notifier
feature tells nova when this port is wired even though nova does not know
about it (doesn't really matter we just log an error). This patch adds a check
to make sure the device_id is a uuid as nova only uses uuids and the debug
agent uses the hostname for device_id.

Change-Id: I04e7195a1fb30bc37e1c0141315c053174f8722c
Closes-bug: #1288582
Removing vim header lines

Simply removes the vim header line and the empty line
following it (when present) for files in the api, db, and
extenssions base directories. In one single _init_ file in
this patchset, all comment lines are removed.

Change-Id: I81b7168dc2ad74b8c30a87e50a531e157851499e
Partial-Bug: 1229324
NSX: Fix pagination support

Add pagination support to the base plugin,
leaving the service plugin unaltered.

Minor tweaks to the UT where required to
avoid intermittent failures caused by random
ordering.

Closes-bug: 1295854

Change-Id: I03e9e104967716046909d6120426e879f714a5c8
Stop using portbindings_db in BSN ML2 driver

Avoids using the portbindings_db in the Big Switch
ML2 driver since ML2 has deprecated that database for
its own version that tracks the same information.

Also eliminates unnecessary 'binding_host' field since
it is now always the same as as the 'portbinding:host_id'
field.

Closes-Bug: #1300628
Change-Id: I17d47cb446cdd2e989c3e0d01b797a81309faaa7
Return 409 for second firewall creation

Second firewall creation returns 500, but it is an expected behavior
of firewall reference implementation and an internal server error
should not be returned.

Change-Id: I9f537b238007d35172e2504591d9d3568ba3a41a
Closes-Bug: #1301105
Merge "NSX plugin: return 400 for invalid gw certificate"
Merge "Removing vim header lines"
Merge "Stop using portbindings_db in BSN ML2 driver"
Merge "Return 409 for second firewall creation"
Merge "Update BigSwitch Name to its correct name"
Merge "Only send notifications on uuid device_id's"
Merge "NSX: Fix pagination support"