restore: detect non-root earlier

restore.sh

@@ -36,10 +36,17 @@
 
   # --- load a transfer plugin
   STORAGE_BIN=`_j_getvar ${STORAGEFILE} "bin"`
+
   if [ -z "$STORAGE_BIN" ]; then
-    # STORAGE_BIN=restic
-    STORAGE_BIN=duplicity
+    if ! id -u | grep '^0$'
+    then
+      cecho error "ERROR: Maybe you need root permissions to start $0"
+    else
+      cecho error "ERROR: missing config bin = ... for file transfer."
+    fi
+    exit 1
   fi
+
   CFGPREFIX=${STORAGE_BIN}_
 
   . `dirname $0`/plugins/transfer/$STORAGE_BIN.sh || exit 1