Windows: protect dir ops by CM_SCACHESYNC_STOREDATA

Windows: protect dir ops by CM_SCACHESYNC_STOREDATA

CM_SCACHESYNC_STOREDATA is used to ensure that only one directory
modifying rpc can be issued to the file server at a time on a
single cm_scache_t.  However, the local directory modifications
were being made after cm_MergeStatus() and cm_SyncOpDone()
were called.  As a result, serialization of changes against the
local directory buffers and b+tree was lost.

Change-Id: I1e99685767b6b9b51e546be0946b189386e8dbd2
Reviewed-on: http://gerrit.openafs.org/6450
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Tested-by: Jeffrey Altman <jaltman@secure-endpoints.com>
Reviewed-by: Jeffrey Altman <jaltman@secure-endpoints.com>