Ensure FC ZoneManager is called

This patch ensures that the FC ZoneManager
is called during for all cases in Cinder
that does a volume attach/detach for FC
enabled drivers.
The problem was that we had code in the volume
manager that manually called the ZoneManager,
after initialize_connection and terminate_connection,
but other places in Cinder were not calling the
ZoneManager.
This patch creates 2 new decorators that can
be used for any driver's initialize_connection
and terminate_connection call.   The decorator
checks to make sure that the return value is for
a fibre_channel attachment and then calls the
ZoneManager's add_connection or delete_connection.
Change-Id: Ie3ae70785f500a140003ad3a8495e0ddc3516ea8
Closes-Bug: 1321798
Fix the section name in CONTRIBUTING.rst

The name of the section "If you're developer, start here"
has changed in the wiki, now is "If you're a developer".
This commit updates it to correctly refer to the
proper section.

Change-Id: Ibc5899d2577187b854213690731136edd4cd74ab
Update cinder generate_sample script

Cinder's generate sample script has fallen a
bit out of date and was no longer working properly
in local venv.

This patch updates it with a working version that
reads the rc file and makes some other updates.

Even better, we'll update the tox.ini file here so
that it actually works, and finally add some more
info to the error message when update check fails
to make is obvious how to run these appropriately.

Change-Id: I2389910d8ece6f737a9609ce4aa05263d9293e14
Merge "Ensure FC ZoneManager is called"
Merge "Fix the section name in CONTRIBUTING.rst"
Merge "Update cinder generate_sample script"