Add a reference to dry run in example

[elecharny]

The page Apply modifications on an LDAP entry on delete show how to apply a modification in an AD server though javascript. When ran in dry mode, the JS code is executed, no matter what, and the modifications are applied.

It is possible to avoid such side effect by checking the nodelete, nocreate, nomodify and nomodrdn flag before applying any action in the script.

The example page would benefit a clarification regarding the dry run mode.