engine: Validate that IDE disk is not read-only

Real IDE disks can't be read-only therefore Engine has to validate it.

Change-Id: I441362adf2f4833b034ede4093fc8195debd2ed5
Bug-Url: https://bugzilla.redhat.com/1057546
Signed-off-by: Sergey Gotliv <sgotliv@redhat.com>