SOLARIS: Switch non-embedded vnodes for Solaris 11

SOLARIS: Switch non-embedded vnodes for Solaris 11

Newer updates to Solaris 11 have been including several changes to the
vnode struct. Since we embed a vnode in our struct vcache, our kernel
module must be recompiled for any such change in order for the openafs
client to work at all.

To avoid the need for this, switch Solaris to using a non-embedded
vnode in our struct vcache. Follow a similar technique as is used in
DARWIN and XBSD, where we allocate a vnode in osi_AttachVnode, and
free it in afs_FlushVCache.

Change-Id: I85fd5d084a13bdea4353b5ad9840fddbc45ce8c0
Reviewed-on: https://gerrit.openafs.org/12696
Reviewed-by: Mark Vitale <mvitale@sinenomine.net>
Reviewed-by: Cheyenne Wills <cwills@sinenomine.net>
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
Reviewed-by: Marcio Brito Barbosa <mbarbosa@sinenomine.net>
Tested-by: Mark Vitale <mvitale@sinenomine.net>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>