* Move IMAGE_POSTPROCESS_COMMAND to truly be what its name implies -- it now

* Move IMAGE_POSTPROCESS_COMMAND to truly be what its name implies -- it now
  occurs after oeimage is called.
* Add ROOTFS_POSTPROCESS_COMMAND, which occurs after rootfs population but
  before oeimage.
* Pass -n option to oeimage, this ensures that the IMAGE_NAME variable used in
  our metadata expansion in oemake is the same as that used by oeimage (it
  parses its own metadata, and would become desynced if IMAGE_NAME
  contained ${DATETIME} or similar).  Note that this is a new option; ensure
  that your 'oe' trees are up to date.

BKrev: 414bd0ddJb2EgJAkAD_JloxA0CdB1w