Break out of FRU read if zero data returned
Break out of FRU read if zero data returned

If a BMC returns 0 data, then assume end of data has been
reached.  Not all implementations accurately advertise FRU
size, so this is a way to detect and break out.

Change-Id: I03d0393563f8527e16830098b649ae940ee7ee9e

openstack/pyghmi,benoit-canet/pyghmi,openstack/pyghmi,stackforge/pyghmi