Add a config override for ViewConfiguration#hasPermanentMenuKey

Allow device overlays to override the behavior of the
hasPermanentMenuKey method at build time. This is useful for devices
that do not behave as the usual autodetection mechanism expects.

Device overlays should set config_overrideHasPermanentMenuKey to 1 if
the device DOES have a permanent menu key or 2 if the device DOES NOT
have a permanent menu key.

Change-Id: I467b68528cf681b08adcaebc2402d8bdd84f6b5c