IMA: handle whitespace better

IMA parser will fail if whitespace is used in any way other than a single
space.  Using a tab or even using 2 spaces in a row will result in a policy
being rejected.  This patch makes the kernel ignore whitespace a bit better.

Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>