Fix one NPE in tethering setting

Once we not declare BT feature, go Setting->more->tethering
will trigger this NPE.
Cherry-picked from AOSP: https://android-review.googlesource.com/#/c/63695/

Change-Id: I4736e7bade261475acda74e26250a81452018ffa
Signed-off-by: Jianzheng Zhou <jianzheng.zhou@freescale.com>
Show memory full text only for internal storage

When the internal memory is full, a warning text is shown
in Settings/Storage. This warning was displayed for all
types of memory (internal/primary, sd card and usb storage)
even though it was only referring to the primary memory.
With this fix, it is only shown for the primary memory.

Change-Id: I35ad4b0b45c6752ddc9d7166495435b27fd4a170
Bleed keyguard widget picker list into translucent bars

Change-Id: Ie929845fd8b822dcf858b9b56cb5758379d55c59
Enable Back-key when go to Emergency call

When go to "Emergency call" from lock screen, back key is disappeared.
It is difficult for user to find the way to go back to previous screen.
This might be bad user experience. So we are going to make it enable.

Change-Id: Iefcca9b8943472c24ddbca6e3ec3441e93e5be91
Merge changes Iefcca9b8,Ie929845f,I35ad4b0b,I4736e7ba into du44

* changes:
  Enable Back-key when go to Emergency call
  Bleed keyguard widget picker list into translucent bars
  Show memory full text only for internal storage
  Fix one NPE in tethering setting