This patch adds the LSM security_syslog hook for controlling the
syslog(2) interface relative to 2.5.59 plus the previously posted
security_sysctl patch.  In response to earlier comments by Christoph,
the existing capability check for syslog(2) is moved into the
capability security module hook function, and a corresponding dummy
security module hook function is defined that provides traditional
superuser behavior.  The LSM hook is placed in do_syslog rather than
sys_syslog so that it is called when either the system call interface
or the /proc/kmsg interface is used.  SELinux uses this hook to
control access to the kernel message ring and to the console log
level.