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

Conflicts:
	packages/SettingsProvider/res/values/defaults.xml
	packages/SettingsProvider/src/com/android/providers/settings/DatabaseHelper.java

Conflicts:
	packages/SettingsProvider/res/values/defaults.xml
Set Settings.Global.WIFI_SCAN_ALWAYS_AVAILABLE default value