update ZFS to 2.1.13

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

diff --git a/submodules/zfsonlinux b/submodules/zfsonlinux
index f5ed5be89a89ff5f7ee76c8caaf2115eac2d46c5..aa261325251022820112c3b8e689ecd033f0e53e 160000 (submodule)
--- a/submodules/zfsonlinux
+++ b/submodules/zfsonlinux
@@ -1 +1 @@
-Subproject commit f5ed5be89a89ff5f7ee76c8caaf2115eac2d46c5
+Subproject commit aa261325251022820112c3b8e689ecd033f0e53e