passwd: Execute delay only if passwd succed

pkg/challenge/passwd.sh

@@ -1,9 +1,10 @@
 #!/bin/sh
 
-/usr/bin/passwd
+/usr/bin/passwd && {
-for i in $(seq 12)
+    for i in $(seq 12)
-do
+    do
-    echo -n .
+        echo -n .
-    sleep 0.4
+        sleep 0.4
-done
+    done
-echo
+    echo " OK"
+}