apparmor: docker-default: Include base abstraction

Encountered problems on 14.04 relating to signals between container
processes being blocked by apparmor. The base abstraction contains
appropriate rules to allow this communication.

Docker-DCO-1.1-Signed-off-by: Michael Brown <michael.brown@discourse.org> (github: Supermathie)

pkg/libcontainer/apparmor/setup.go

@@ -18,6 +18,7 @@ const DefaultProfile = `
 @{PROC}=/proc/
 
 profile docker-default flags=(attach_disconnected,mediate_deleted) {
+  #include <abstractions/base>
   network,
   capability,
   file,