Revert "Revert "put back the unused virtuals in Vector<>""

This reverts commit 225c66a48cdc3acef21ee380dc134449749d3cb3

Change-Id: If31a04b81052cbc7dd7bf237c07107c33066d03d

Conditionally Revert "put back the unused virtuals in Vector<>"

These symbols are needed for MR2 camera.tegra and other blobs,
but they conflict with KK blobs so define it for devices that
need it by setting COMMON_GLOBAL_CFLAGS += -DNEEDS_VECTORIMPL_SYMBOLS

Change-Id: I59e66074526f013918a29c3afc10e52b9812778c