Patch from Krzysztof Blaszkowski:

Patch from Krzysztof Blaszkowski:

i noticed this issue running simple iscsi connection test to a few targets.
without included patch the active_pages_total counter wraps around 0 thus it
breaks logic for releasing memory on "hi watermark" just like it is depicted
in:

Inactive/active pages                      18/-25
Hi/lo watermarks [pages]                   119808/0
Hi watermark releases/failures             4/0

git-svn-id: https://scst.svn.sourceforge.net/svnroot/scst/trunk@676 d57e44dd-8a1f-0410-8b47-8ef2f437770f