Keyguard: Set WIDGET_CATEGORY_KEYGUARD when AppWidgetHostView is created

Allows the default lockscreen widget to inherit the keyguard widget
host category.  Without this, only widgets added through
KeyguardActivityLauncher are assigned the correct
OPTION_APPWIDGET_HOST_CATEGORY.

Change-Id: Ic97818d85ca5f00da0ce43bb36006d66a6935363
Initialize pointer members to NULL to avoid illegal reference

mBitmap and mTexture is not initialized to NULL which causes
illegal address access when it fails to be created from
oversized bitmap.
Cherry-picked from AOSP: https://android-review.googlesource.com/#/c/79320/

Change-Id: Iea54bec8788bc5f3a10040fdb43f416c0d41a14c
Set Settings.Global.WIFI_SCAN_ALWAYS_AVAILABLE default value

To be able to customize the "WiFi scan always available"
setting we need to set a default value.

Change-Id: I3673f2613ab9b6a947aed7e29d4cc876140c2180