Since pinsyscalls(2) applies to all system calls and does a more precise

Since pinsyscalls(2) applies to all system calls and does a more precise
check earlier, the pinsyscall(SYS_execve mechanism has become redundant.
It needs to be removed delicately since ld.so and static binaries use it.
As a first step, neuter the checking code in sys_execve().  Further steps
will follow slowly.
ok kettenis