This removes the '@credentials' syscall set that was added in commit
v234-468-gcd0ddf6f75.
Most of these syscalls are so simple that we do not want to filter them.
They work on the current calling process, doing only read operations,
they do not have a deep kernel path.
The problem may only be in 'capget' syscall since it can query arbitrary
processes, and used to discover processes, however sending signal 0 to
arbitrary processes can be used to discover if a process exists or not.
It is unfortunate that Linux allows to query processes of different
users. Lets put it now in '@process' syscall set, and later we may add
it to a new '@basic-process' set that allows most basic process
operations.
09d3020b0a