Bug #1057238
CVE-2012-2244

Currently, files that are saved by Mahara use the
directorypermissions config option, which defaults to
0700, which allows execution.

This allows users to potentially upload files with
executable bits set, and if they have control of the
config options pathtoclam, pathtozip, or pathtounzip
then they could run this command when one of those
commands are invocated.

This patch bitwise-AND's the directory permissions
config with 0666, which removes any executable bit
and sets the result as a new config option
filepermissions.

A change the upload code to use this new option is made

Change-Id: I088d9873de7797d5a9aefc2401301f8b855ed592
Signed-off-by: Hugh Davenport <hugh@catalyst.net.nz>