DEVEL15-windows-nim-afs-20070617

DEVEL15-windows-nim-afs-20070617

Don't assume that WM_DESTROY is the final message received by a
window.  Verify dialog data structures when handling messages and
reset the window data field when freeing the data structure.

Zero should be considered a valid credentials type identifier in
Network Identity Manager.

When checking if an identity is configured to obtain a token for a
specific cell, don't go through the list of cells if AFS tokens
are disabled for the identity.

Similarly, when removing a token for a specific cell from all
identities, don't bother modifying identities for whom AFS tokens
are disabled.

Keep track of whether a specific cell was added to the list of
cells to authenticate for an identity because it was listed in the
configuration or because a token for the cell already existed.

Correct an off-by-one error when calculating buffer sizes for
multi strings which failed to account for a double NULL
terminator.

Don't update the cell->identity mapping if a token for that cell
could not be obtained.

If the list of cell to authenticate for an identity is empty, we
still need to write the empty string to the configuration.
Otherwise, removing all the tokens from an identity will not
result in a configuration change reflecting that.

(cherry picked from commit 6bc5c0899a9eb6c134c0079406fe28113e5cbeaf)