pre-revprop-change — Notification of a revision property change attempt.
The pre-revprop-change hook is run
          immediately prior to the modification of a revision property
          when performed outside the scope of a normal commit.  Unlike
          the other hooks, the default state of this one is to deny
          the proposed action.  The hook must actually exist and
          return a zero exit value before a revision property
          modification can happen.
If the pre-revprop-change hook
          doesn't exist, isn't executable, or returns a nonzero exit
          value, no change to the property will be made, and anything
          printed to stderr is marshalled back to the client.
The command-line arguments passed to the hook program, in order, are:
Repository path
Revision whose property is about to be modified
Authenticated username attempting the property change
Name of the property changed
Change description: A (added),
              D (deleted), or M
              (modified)
Additionally, Subversion passes the intended new value of the property to the hook program via standard input.