TOMOYO: Fix memory leak upon file open.

In tomoyo_check_open_permission() since 2.6.36, TOMOYO was by error
recalculating already calculated pathname when checking allow_rewrite
permission. As a result, memory will leak whenever a file is opened for writing
without O_APPEND flag. Also, performance will degrade because TOMOYO is
calculating pathname regardless of profile configuration.
This patch fixes the leak and performance degrade.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>