contrib/shell/kedifa_generateauth: Do not fail silently when kedifa does not provide an identifier

Also, make the output a bit nicer.

contrib/shell/kedifa_generateauth

@@ -58,11 +58,16 @@ else
 fi
 trap 'rm "${outfile}"' EXIT
 chmod go= "$outfile"
-echo -n "Retrieving kedifa identifier for shared instance..."
-kedifa_auth="$(curl --silent --cacert "${cafile}" --crlfile "${crlfile}" "${kedifa_url_base}/generateauth")"
+echo -n "Retrieving kedifa identifier for shared instance... "
+if kedifa_auth="$(curl --silent --fail --cacert "${cafile}" --crlfile "${crlfile}" "${kedifa_url_base}/generateauth")"; then
+  :
+else
+  echo "failed: kedifa did not provide an identifier"
+  exit 1
+fi
 trap - EXIT
 printf 'CA=%q\nCRL=%q\nURL=%q\n' "$cafile" "$crlfile" "${kedifa_url_base}?auth=${kedifa_auth}" > "$outfile"
-echo " done."
+echo "done."
 if curl --output /dev/null --silent "https://$domain"; then
   :
 elif [ 35 -eq $? ]; then