Revert "apparmor: add base infastructure for socket mediation"

This reverts commit 651e28c5.

This caused a regression:
 "The specific problem is that dnsmasq refuses to start on openSUSE Leap
  42.2.  The specific cause is that and attempt to open a PF_LOCAL socket
  gets EACCES.  This means that networking doesn't function on a system
  with a 4.14-rc2 system."

Sadly, the developers involved seemed to be in denial for several weeks
about this, delaying the revert.  This has not been a good release for
the security subsystem, and this area needs to change development
practices.

Reported-and-bisected-by: James Bottomley <James.Bottomley@hansenpartnership.com>
Tracked-by: Thorsten Leemhuis <regressions@leemhuis.info>
Cc: John Johansen <john.johansen@canonical.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Seth Arnold <seth.arnold@canonical.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>