String addition

[Elijah Newren <newren gmail com>]

Hi,

metacity/src/metacity.schemas.in had some string additions due to a
new pref.  The addition is limited to a single short description and
corresponding long description of the new GConf key.  It's not a very
user-visible string (I had to grep the .po files to verify that GConf
key descriptions were actually translated), so not real high priority.

Cheers,
Elijah