Fix shellcheck errors

libexec/sourcezap/commands/sourcezap-teardown

@@ -17,7 +17,7 @@ user=_sourcezap
 if [ "$(id -u)" = "0" ]; then
     pw userdel  -n "${user}"  || true
     pw groupdel -n "${user}"  || true
-    rm -rf /home/"${user}"/  || true
+    rm -rf /home/"${user:?}"/ || true
     printok "done"
 else
     printerr "you must be root"

libexec/sourcezap/setup/setup-doas

@@ -16,8 +16,7 @@ sharedir="${localbase}"/share/sourcezap
 # main
 src="${sharedir}"/doas.conf
 dest="${localbase}"/etc/doas.conf
-cat "${src}" |
-while read -r line; do
+while read -r line < "${src}"; do
     if grep -q "${line}" "${dest}"; then
         continue
     fi