KEYS: Add an alloc flag to convey the builtinness of a key

KEYS: Add an alloc flag to convey the builtinness of a key

BugLink: http://bugs.launchpad.net/bugs/1569924
Add KEY_ALLOC_BUILT_IN to convey that a key should have KEY_FLAG_BUILTIN
set rather than setting it after the fact.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
(cherry picked from commit 5d2787cf0b210d2925e8d44e2e79241385249d6b)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Andy Whitcroft <andy.whitcroft@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>