Fix the SMB2 showstopper, found by an extended torture test from Volker.

Fix the SMB2 showstopper, found by an extended torture test from Volker.

In the oplock refactoring, the algorithm underwent an unnoticed change.
In 3.5.x stat_opens were silently (i.e. no explicit code had comments
explaining this) ignored when looking for oplock breaks and share mode
violations. After the refactoring, the function find_oplock_types()
no longer ignored stat_open entries in the share mode table when looking
for batch and exclusive oplocks. This patch adds two changes to find_oplock_types()
to ignore the case where the incoming open request is a stat open being
tested against existing opens, and also when the incoming open request
is a non-stat open being tested against existing stat opens. Neither
of these cause an oplock break or share mode violation. Thanks a *lot*
to Volker, who persevered in reproducing this problem.

Autobuild-User: Jeremy Allison <jra@samba.org>
Autobuild-Date: Mon May 16 22:38:20 CEST 2011 on sn-devel-104
(cherry picked from commit 8cf14c21b3bc55454728bf48b23f696e15c92aea)
(cherry picked from commit a2bc1d37b98a0581960039a5ff3deb55cf0c4f90)