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

This reverts commit 11b9acf7651bc73dc72df950cd074fee743ce5c9.

Change-Id: I00efd8f68d449e656786b436128f0bf1d14a81c6
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