- Fix style in vm_page_lookup(): there is no whiteline between   assertions and other code in this file. - Reinsert some comments that were lost during the work but which are   actual yet, reducing differences with HEAD.
- Fix style in vm_page_lookup(): there is no whiteline between
  assertions and other code in this file.
- Reinsert some comments that were lost during the work but which are
  actual yet, reducing differences with HEAD.

Sponsoed by:	EMC / Isilon storage division

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase