classes/buildhistory: record size of installed package not compressed archive

classes/buildhistory: record size of installed package not compressed archive

* usually it's more important to know how much space will each
  package take on target device then size of compressed package
* example for libewebkit0 with 4 different architectures, interesting
  that om_gta02 .ipk is bigger but it's smaller when installed

  before:
  MACHINE     DEFAULTTUNE       SIZE (.ipk file)
  om_gta04    cortexa8t-neon    15996 KiB libewebkit0
  qemux86_64  x86-64            16992 KiB libewebkit0
  spitz       xscale            16148 KiB libewebkit0
  om_gta02    arm920t           16260 KiB libewebkit0

  after:
  MACHINE     DEFAULTTUNE       SIZE (installed)
  om_gta04    cortexa8t-neon    60544 KiB libewebkit0
  qemux86_64  x86-64            63720 KiB libewebkit0
  spitz       xscale            60588 KiB libewebkit0
  om_gta02    arm920t           56268 KiB libewebkit0

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>