init.qcom.usb.rc: Set serial string on init

Currently init.qcom.usb.sh is writing the serial number into
android sysfs entry. But during bootup, .rc file is writing
default composition before .sh gets executed. This results USB
driver sending default serial string to host due to port hopping
happens. Hence write ro.serialno to the sysfs entry on init once.

Also remove reading persist.usb.serialno which is required only for
NAND based devices as all future targets are emmc based devices.

CRs-Fixed: 659235
Change-Id: Iddb0875fe0aff9aa9d53850861cc54735e5006d7
Merge "init.qcom.usb.rc: Set serial string on init"
Merge 69c9b448f7808a38475ae465ddf6d85c79740745 on remote branch

Change-Id: I8cb53dbb3cc711ce4a673fe503a4a72fea13475f
Sign recovery image

LK now requires recovery image to be signed. This
is a new change to ensure that only signed images
are used.

Change-Id: I25fef9c311370e3f26d2d09b577575cd2a16f880
Merge "Sign recovery image"
common: add support to sign boot image

adding rules for generating signed boot image

Change-Id: I53710c2b4b8e8750c29d9c46c51a3e4ff0f270d2
Merge df41187715e2b89f663f90b246f322831618aea8 on remote branch

Change-Id: Ie7be8fc472bfd0486c42065292b69eb9825a5099
Merge "common: add support to sign boot image"
Merge 03468fb9b03ae4827f0c32e336cd95cf046bcb86 on remote branch

Change-Id: I3120b1c09b4379f752c3974592ba22fdb9348326
Merge "Merge 03468fb9b03ae4827f0c32e336cd95cf046bcb86 on remote branch"