Put selinux in permissive mode by default via a runcmd in cloudconfig

Change-Id: I7db02a967de9a3e85876901163f7611196a9429f
Signed-off-by: Steven Dake <sdake@redhat.com>

heat/cloudinit/config

@@ -1,3 +1,6 @@
+runcmd:
+ - [ setenforce, 0 ]
+
 user: ec2-user
 
 cloud_config_modules:
@@ -7,3 +10,4 @@ cloud_config_modules:
  - timezone
  - update_etc_hosts
  - update_hostname
+ - runcmd