libgui: Don't assign handle to NULL after free

This reverts c784dfc3 for exynos4 devices
with Mali 400 GPUs, which causes a fatal signal (SIGSEGV) and death of
the graphics subsystem

Change-Id: I6dbf8f8664fca01baf63fece7c64016609fe3e1c

libgui: Don't assign handle to NULL after free is common

Reportedly Mali and PowerVR GPUs are crashing when setting handle to NULL
So we will set a flag for the devices that might need this aswell

Set BOARD_EGL_NEEDS_HANDLE_VALUE=true in BoardConfig.mk to use

Change-Id: I6c967f62dc6adced7583d7b2045d11cf5b25fc80