buildsbepart: sort EC images for consistent output
buildsbepart: sort EC images for consistent output

Perl default enumeration over hash keys doesn't seem to be
stable.  In order to make a reproducible build sort the EC
images so they end up in the same order each time.

Resolves #115

Signed-off-by: Robert Lippert <c065cdb6ddd7bea176bf96c0c5ae92b2a677c1e0@google.com>
Change-Id: I82861ce8dbc0cb8e24fd68eeffcf10d1f06e51d5
Reviewed-on: http://ralgit01.raleigh.ibm.com/gerrit1/47963
Tested-by: Jenkins Server <8e3f934e4c44875bc48d33da3ea13d93ba9a233f@us.ibm.com>
Tested-by: Jenkins OP Build CI <e610bd72261d3c0a48f1e8ae36832ab00774d426@us.ibm.com>
Tested-by: Jenkins OP HW <0eb0fff262f74a65a832afbcc7b153e391c9a3fd@us.ibm.com>
Tested-by: FSP CI Jenkins <aa9e4d9ac7cd25905e9c0dd36d4150516e73dd86@us.ibm.com>
Reviewed-by: Daniel M. Crowell <912029ca9254ac7b5854e56910561d682e1fa2d0@us.ibm.com>

open-power/hostboot,open-power/hostboot,open-power/hostboot,open-power/hostboot,open-power/hostboot