[linux seccomp] Allow getpid to worker and main
[linux seccomp] Allow getpid to worker and main

Stats requires getpid now in the worker threads. Main thread requires it
to generate coverage in debug mode.

gencer/memcached,guikcd/memcached,gencer/memcached,dormando/memcached,guikcd/memcached,dormando/memcached,guikcd/memcached,memcached/memcached,dormando/memcached,dormando/memcached,memcached/memcached,gencer/memcached,memcached/memcached,dormando/memcached,guikcd/memcached,memcached/memcached,gencer/memcached,memcached/memcached,gencer/memcached,guikcd/memcached