Code review comment for lp:~dannf/maas-images/arm64-netinst-restructure

for reference... here is what I did to verify this is sane.

- added bin/netboot-mirror and README.di-scraping
  these probalby woudl have been helpful for you.. in seeing what is going
  on. and explaining things.

- ran from your proposed merge:
    ./bin/netboot-mirror --no-item-download out-new.d
  and from original:
    ./bin/netboot-mirror --no-item-download out-old.d

  That created out-old.d and out-new.d which contains streams data for the NetbootMirrorReader

- got a list of fields in there, and flattened and sorted output.
  run:
    sstream-query --pretty out-old.d/streams/v1/com.ubuntu.installer:released:netboot.json
  That dumps all fields for each item... looks like:
    {'arch': 'i386',
     'basename': 'linux',
     'content_id': 'com.ubuntu.installer:released:netboot',
     'format': 'products:1.0',
     'ftype': 'kernel',
     'image-format': 'default',
     'item_name': 'ututgenke0.default',
     'item_url': 'out-old.d/files/utopic/i386/20101020ubuntu349/utopic/generic/kernel.default',
     'kernel-flavor': 'generic',
     'kernel-release': 'utopic',
     'md5': '4237d65fc81b909684447bf54fd02ce9',
     'path': 'files/utopic/i386/20101020ubuntu349/utopic/generic/kernel.default',
     'pocket': 'release',
     'product_name': 'com.ubuntu.installer:netboot:14.10:i386',
     'pubdate': 'Fri, 17 Oct 2014 15:53:00 +0000',
     'release': 'utopic',
     'sha256': '479619cc6522efb1ceb591bb425fd85d3735e2306de24a1e4345de01a209017c',
     'size': '6077104',
     'version': '14.10',
     'version_name': '20101020ubuntu349'}

- cleaned up the list of fields i wanted to compare to make sure old and new are similar.
  then, sorted that output and diffed them.

  base="%(product_name)s/%(version_name)s/%(item_name)s"
  extra="%(release)s %(version)s %(pocket)s %(kernel-flavor)s %(ftype)s %(image-format)s %(kernel-release)s %(md5)s %(path)s"
  path=streams/v1/com.ubuntu.installer:released:netboot.json

  sstream-query --output-format="$base $extra" out-old.d/$path | sort > old.list
  sstream-query --output-format="$base $extra" out-new.d/$path | sort > new.list

  Then, just diff them
   http://paste.ubuntu.com/11503207/

  Your new had only new entries, and only in wily... so that seems good.