fsck: Only print "marking commit partial" once

Let's only print if the commit isn't already partial; this
addresses a spam of "marking commit partial" from fsck.

Closes: #1548
Approved by: cgwalters

tests/installed/nondestructive/itest-pull.sh

@@ -35,11 +35,12 @@ echo "ok pull"
 # fsck marks commits partial
 # https://github.com/ostreedev/ostree/pull/1533
 for d in $(find bare-repo/objects/ -maxdepth 1 -type d); do
-    (find ${d} -name '*.file' || true) | head -20 | xargs rm -vf
+    (find ${d} -name '*.file' || true) | head -20 | xargs rm -f
 done
-if ostree --repo=bare-repo fsck; then
+if ostree --repo=bare-repo fsck |& tee fsck.txt; then
     fatal "fsck unexpectedly succeeded"
 fi
+assert_streq $(grep -cE -e 'Marking commit as partial' fsck.txt) "1"
 ostree --repo=bare-repo pull origin ${host_nonremoteref}
 # Don't need a full fsck here
 ostree --repo=bare-repo ls origin:${host_nonremoteref} >/dev/null