bugfix: assemble_authorized_keys now handles missing keys properly

(cherry picked from commit e61190d5)

run.sh

@@ -38,9 +38,10 @@ function assemble_authorized_keys {
         fi
         
         # let's check if the pubkey file(s) exists, shall we?
-        KEYFILES="$( compgen -G "${PUBKEYDIR}/${KEYGLOB}" )"
+        # '|| true' needed because we're in a `set -e` situation
+        KEYFILES="$( compgen -G "${PUBKEYDIR}/${KEYGLOB}" || true )"
         # did we find anything?
-        if [ $? == 0 ]; then
+        if [ "$KEYFILES" != "" ]; then
         
             echo "        +-- found keyfile(s), processing..."
             # the IFS is conveniently already set to newline and newline only