tests: Update hashes for test/pkg/*

with cwd of test this was done with:
for i in pkg/* ; do make --no-print-directory -C $i show-tag; done | ( IFS=: ; while read image hash ; do ../scripts/update-component-sha.sh --image $image $hash ; done )

Note that `linuxkit/test-virtsock` (built by `test/pkg/virtsock`) does not
appear to be referenced anywhere.

Signed-off-by: Ian Campbell <ijc@docker.com>

test/pkg/ns/template.yml

@@ -14,7 +14,7 @@ onboot:
     - type: cgroup
       options: ["rw"]
   - name: poweroff
-    image: linuxkit/poweroff:bce51402e293da0b653923a43c3c7be6e0effa05
+    image: linuxkit/poweroff:3845c4d64d47a1ea367806be5547e44594b0fa91
     command: ["/bin/sh", "/poweroff.sh", "3"]
 trust:
   org: