fix creation of substreams for OLE2

Change-Id: Idade93bcc1981543357e849b2faf075e7a021d3e
generalize this for Zip too

Change-Id: I9ca0676f056fe3f09821c208ff095beb1f3c19ac
reading from a stream must start at the beginning

Change-Id: I0c668244fffcda04a8fe34ef629754f5935cab4b