profile/base/nova: declare nova class and configure cache correctly.

profile/base/nova: declare nova class and configure cache correctly.

Nova {} workaround is not working correctly, we need to merge this patch
so we can move out ::nova from THT completely.

Also we need to use nova::cache to configure memcached parameters.

Co-Authorized-By: Giulio Fidente <gfidente@redhat.com>
Co-Authorized-By: Sven Anderson <sven@redhat.com>
Co-Authorized-By: Emilien Macchi <emilien@redhat.com>
Depends-On: I52d5badb9960124bb8fcb54983db2853c4185e77
Depends-On: I3e400a5f64b85f0d374fc02cc5e4080d19d0f2e4
Depends-On: Iee5f8015cbf40ca0e9a435a7de919ebdb74cf93f

Change-Id: Ie4e72e765f6a8ade48d4b2b766f067872554d1a2