sync periodic_task fix from incubator

Set the value of time the periodic task was last run to a multiple of the
spacing value rather than the actual last time run. This ensures tasks runs
regularly but avoids synchronizing that interval with other nodes.

This patch also removes the coalescing of tasks which are _nearby_ (0.2
seconds away).

4dbd3aa Make periodic tasks run on regular spacing interval
21249f1 Fix parenthesis typo misunderstanding in periodic_task

Change-Id: I8873545578f104fd204fbc25493350128b2bc8d4
update vsm credential correctly

Today if we modify the n1kv VSM credential in the cisco_plugins.ini, the
older VSM ip address remains in the db, and all requests are sent to
the older VSM. This patch deletes all n1kv VSM credentials on neutron
start up before adding the newer VSM credentials. Hence making sure
that there is only one n1kv VSM IP address and credential in the db.

Change-Id: I772a86bf896a1d3d9c69c545ce6918b0fe3a2e48
Closes-Bug: #1341014
VMWare: don't notify on disassociate_floatingips()

L3 agent notifications don't make sense for NSX VMWare plugin since
there is no L3 agent in such setup, so disabling them here.

Updated a unit test to check that notification is indeed not requested.

Change-Id: I9c7c32d02d466098d22df8f10448361c3d99174c
Related-Bug: 1330955
Encapsulate some port properties in the PortContext

Bindings to host or status may need further encapsulation
to avoid exposing mechanism drivers to underlying DB model
details. This was particularly true in the case of the
l2pop mech driver.

As a result, some docstrings were reworded, and the newly
introduced properties used directly in the mech drivers.

Partially-implements: blueprint neutron-ovs-dvr
Supports blueprint: ml2-hierarchical-port-binding

Change-Id: If2a373ef04d19b164585fb4bde4fe6e0cfaf43be
Merge "sync periodic_task fix from incubator"
Merge "VMWare: don't notify on disassociate_floatingips()"
Merge "update vsm credential correctly"
Merge "Encapsulate some port properties in the PortContext"