Fix parsing of network_id reservation parameter
Fix parsing of network_id reservation parameter

The network_id parameter was not defined in CREATE_RESERVATION_KEYS. As
a result, it could not be parsed by the command-line client.

Change-Id: Icad6533ea32967601cf8d3bd4ccee659bb0b5abd
Closes-Bug: #1840759

ChameleonCloud/python-blazarclient,openstack/python-blazarclient,stackforge/python-blazarclient