[rsbac] can't permit execute with FF for "power users"

[Bencsath Boldizsar]

> Power user:
> 
> pingtomi at pingtomi:/tmp$ sh x.sh
> 
> total 64
> -rw------- 1 root     root       625 2006-09-25 06:25 file2Go3kb
> -rw------- 1 root     root       626 2006-09-24 06:25 fileDZCLR0
> ˙˙

doing 'sh' is interpreting a text file as a script. It is not executing 
the script. Of course, you can sh x.sh even if x.sh does not have 
executable mark.

And yes, there might be possible ways to bypass security measures with 
tricks like that for non-script files also.