Fix dry mode for find/chmod

In local install, the files could be present, so relying on find to find
nothing did not work.  chmod must be properly sandboxed.

src/include/deploy.sh

     then
         _maybe mkdir -vp "$(dirname "$dst")"
         _maybe cp -Tvr "$src" "$dst"
-        find "$dst" -type f -print0 | xargs -0 chmod -c "$mode"
+        find "$dst" -type f \
+          | while read chmod_item;
+            do
+                _maybe chmod "$mode" "$chmod_item"
+            done
     else
         _maybe install -DTvm "$mode" "$src" "$dst"
     fi