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 "Merge "init.qcom.usb.rc: Set serial string on init""
Merge 5c0215a4a1dabf185220608b904f0aa2f3244df4 on remote branch

Change-Id: I7c4a21e2938df2184c7bc86e2c509cd26bc64366
Merge "Merge 5c0215a4a1dabf185220608b904f0aa2f3244df4 on remote branch"
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"
Merge "Merge "Sign recovery image""
common: add support to sign boot image

adding rules for generating signed boot image

Change-Id: I53710c2b4b8e8750c29d9c46c51a3e4ff0f270d2
Merge "common: add support to sign boot image"
Merge "Merge "common: add support to sign boot image""
Merge 683a52439b068b5766734c809942d3c5b46c7caf on remote branch

Change-Id: I1594ab605965930194c8ef7b3b4ee3680ec1ba79
Merge "Merge 683a52439b068b5766734c809942d3c5b46c7caf on remote branch"