This change move "do_extra_package_install" from pre-install to install
phase.
Extra packages are added by user request using the flag "-p", This
package should not be something the elements depend on.
The reason behind this patch is to move the extra package install to
a proper phase, Also more reasonable if base element run package update
to be before we install extra packages.
Change-Id: I68cc773aba9aa01743f0dda9f4e635e4cac2a282
