Run postinst during rootfs generation

Background

In poky we have 2 types of postinst scripts: one (type-1) can be (and has already been) run at rootfs generation time and the other (type-2) has to be delayed to the first-boot of target device. Type-2 makes target device's first-boot slow and it would be great if we can fix it and convert it to type-1.

1.1 tasks

• We can instrument a first-boot with minimal/sato first to see which postinstalls take the most time and then prioritise those ones to fix.

• Dexuan has figurerd out a list of 33 recipes in total(recipes with the same name but with different versions are counted once) we possibly need to fix. For the recipes, we need try to find recipe-specific ways(use appropriately modified native utilities to generate caches, files, etc as necessary on the target filesystem).

   11 recipes: these could be easily fixed if we add the properly-adjusted utilities "adduser, addgroup, pwconv, etc". Scott is actually adding the utilites: http://git.pokylinux.org/cgit/cgit.cgi/poky-contrib/commit/?h=sgarman/useradd-rebased&id=99e54d9696104ed38ec1e3464e17aa1f9b8d98ac

meta/recipes-devtools/distcc/distcc_2.18.3.bb meta/recipes-extended/cronie/cronie_1.4.7.bb meta/recipes-extended/at/at_3.1.12.bb:47 meta/recipes-support/hal/hal.inc:45 meta/recipes-core/dbus/dbus.inc:49 meta/recipes-connectivity/openssh/openssh_5.8p2.bb meta/recipes-connectivity/ppp-dialin/ppp-dialin_0.1.bb meta/recipes-graphics/x11-common/xserver-nodm-init.bb meta/recipes-multimedia/pulseaudio/pulseaudio.inc:87 meta/recipes-extended/shadow/shadow_4.1.4.3.bb:125 meta/classes/libc-package.bbclass