NetApp api fix structure conversion methods

This fixes the issue in api element creation
when data structures are supplied to be converted
into NaElements. It could not handle multiple
keys with same name and also not converted different
types properly into NaElement. This change fixes the issue.

Change-Id: I84f1ee97a73bbad88bbb64d4a9ac4e1b29cad741
Closes-bug: #1287643
Add snapshot related data to limits api

When calling the limits api we can only get Volume and Gigabyte data,
the snapshot related limit value should be returned too.

Change-Id: I6a5e1e2d1aa6abbac5d5dacd042223ce49207c1f
Closes-bug: 1282924
Fix create_export/remove_export in driver.py

1. There was a call to rpcapi.create_export which does not have a
matching volume manager function, causing volume migration to crash.
This call was not necessary because there is already an
initialize_connection RPC call, which calls the driver's create_export
function. Removed the create_export RPC call and function. Added better
error handling to that code in _attach_volume in driver.py as well.

2. The manager called remove_export from detach_volume, which was not
being called by these functions. I believe it makes more sense to call
it from terminate_connection. Moved it there, and fixed up the
corresponding code in _detach_volume in driver.py.

3. Remove leftovers of export code from create_volume manager flow.

Change-Id: I2b192630ebed54368f151db47b49cbc72601a8d7
Closes-Bug: #1285060
Merge "NetApp api fix structure conversion methods"
Merge "Fix create_export/remove_export in driver.py"
Merge "Add snapshot related data to limits api"
(Test commit) Change README to reflect Jio's fork of Cinder

Change-Id: I3f26c0a736e63725aec24ca2fa12c707b8e6460f