Fix Storwize/SVC storage_protocol reporting.

The Storwize/SVC driver supports both FC and iSCSI protocols
simultaneously. Therefore, 'storage_protocol' should be defined as a
list of enabled protocols, not simply 'iSCSI'. The extra_specs
key-value would then be, for example, storage_protocol='<in> iSCSI'
or storage_protocol='<in> FC'.

Fixes bug: 1142196

Change-Id: Ib99a6d4e4e61d07ddb4f173c13fe7e9f5482fa2b
Merge "Fix Storwize/SVC storage_protocol reporting."