Smack: Verify read access on file open - v3

Smack: Verify read access on file open - v3

Smack believes that many of the operatons that can
be performed on an open file descriptor are read operations.
The fstat and lseek system calls are examples.
An implication of this is that files shouldn't be open
if the task doesn't have read access even if it has
write access and the file is being opened write only.

Targeted for git://git.gitorious.org/smack-next/kernel.git

Change-Id: I63d57bc62cd08fa4e1f128b544e7ed7316456e4c
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>