Big Switch: Only update hash header on success

This patch moves the hash update call into the success block
of the server manager so the database isn't updated with
a hash header from an error response. Additionally, it prevents
the hash from being updated to an empty value if the hash header
is not present in the response.

Closes-Bug: #1348766
Change-Id: I512d01f9bb91b208dd58883d2464951ecc6748e1
Remove redundant topic from rpc calls

RpcProxy sets by default topic=self.topic, there's no need to specify
it explicitly in derived class, unless it is overridden

Change-Id: I19b9a67072a7f3c42e3b0e4ba412241a056a79a3
Closes-bug: 1348180
Radware: When a pip is needed, reuse the Port

When a pip (Proxy IP) is needed by the driver, do not create
a new Neutron Port every time a pip is needed. Reuse the
existing Port.

Change-Id: I769a9d85e217b30a1ea4d09449ff39bf1ab23c5a
Closes-bug: #1349895
Merge "Big Switch: Only update hash header on success"
Merge "Remove redundant topic from rpc calls"
Merge "Radware: When a pip is needed, reuse the Port"