heat templates : Remove IAM Policy sections

Some templates have Policies specified for the User
resource in the AWS IAM Policy format, which we do
not yet support, and will confuse users now we have
OS::Heat::AccessPolicy implemented

ref bug 1115758

Change-Id: I6958b02fe6518ea43729ebc18818524ae7e4921e
Signed-off-by: Steven Hardy <shardy@redhat.com>