SELinux: ss: Fix policy write for ioctl operations

Security server omits the type field when writing out the contents of the
avtab from /sys/fs/selinux/policy. This leads to a corrupt output. No impact
on the running kernel or its loaded policy. Impacts CTS neverallow tests.

Bug: 20665861
Change-Id: I657e18013dd5a1f40052bc2b02dd8e0afee9bcfb
Signed-off-by: Jeff Vander Stoep <jeffv@google.com>