update ZFS to 0.8.2

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>

diff --git a/submodules/zfsonlinux b/submodules/zfsonlinux
index 69255727d071ac571e382f1629cc778f319ca8e3..97bcaf4bef7552eeb3c48bdfad0c85b7800ee690 160000 (submodule)
--- a/submodules/zfsonlinux
+++ b/submodules/zfsonlinux
@@ -1 +1 @@
-Subproject commit 69255727d071ac571e382f1629cc778f319ca8e3
+Subproject commit 97bcaf4bef7552eeb3c48bdfad0c85b7800ee690