Fix configurations reference for SPICE

The following options appear:
enabled = False	      (BoolOpt) enable spice related features
enabled = False	      (BoolOpt) Whether the V3 API is enabled or not

The option about V3 API is for nova v3 api, a mistake was also
fixed on nova.flagmappings.

Change-Id: I110f860dd220da4dcdf573b42f67abaee1945c22
Closes-bug: #1266977
Merge "Fix configurations reference for SPICE"