disk-deactivate: only run zfs command if they are present

disk-deactivate/disk-deactivate.jq

@@ -1,7 +1,7 @@
 # since lsblk lacks zfs support, we have to do it this way
 def remove:
   if .fstype == "zfs_member" then
-    "zpool destroy -f \(.label)"
+    "if type zpool >/dev/null; then zpool destroy -f \(.label); fi"
   elif .fstype == "LVM2_member" then
     [
       "vg=$(pvs \(.path) --noheadings --options vg_name | grep -o '[a-zA-Z0-9-]*')",
@@ -14,7 +14,7 @@ def remove:
     # maybe its zfs
     [
       # the next line has some horrible escaping
-      "zpool=$(zdb -l \(.path) | sed -nr $'s/ +name: \\'(.*)\\'/\\\\1/p')",
+      "zpool=$(if type zdb >/dev/null; then zdb -l \(.path) | sed -nr $'s/ +name: \\'(.*)\\'/\\\\1/p') else echo ""; fi",
       "if [[ -n \"${zpool}\" ]]; then zpool destroy -f \"$zpool\"; fi",
       "unset zpool"
     ]