Windows: Add CM_MERGEFLAG_CACHE_BYPASS

If a store operation is performed direct to the file server
bypassing the AFSCache, call cm_MergeStatus() with
CM_MERGEFLAG_CACHE_BYPASS to ensure that the valid version
numbers for the cm_scache_t object are incremented appropriately.
After a cache bypass occurs, only buffers with the current
data version number are valid since the cached data will be
incomplete.

Reviewed-on: http://gerrit.openafs.org/8964
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Tested-by: Jeffrey Altman <jaltman@your-file-system.com>
(cherry picked from commit 8b62d08760b2cde9fb0b15b695d8467191c0669f)

Change-Id: Ic0f3d4629324c3cf39eff469f02ffd16653f09d8
Reviewed-on: http://gerrit.openafs.org/9039
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Windows: Set dirty page limit to 2 x ChunkSize / 4096

4096 is the size of a memory manager page.  ChunkSize is in octets.
Windows doesn't wait until the limit is reached to begin flushing
and ChunkSize is not a hard limit.

Reviewed-on: http://gerrit.openafs.org/8965
Reviewed-by: Rod Widdowson <rdw@steadingsoftware.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>
Tested-by: Jeffrey Altman <jaltman@your-file-system.com>
(cherry picked from commit 5be1779547d800e1a040fe1969336adab0c01afa)

Change-Id: I1b969f1cb486bc01675771d1c291594ae6b55e5d
Reviewed-on: http://gerrit.openafs.org/9040
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@your-file-system.com>