Add getExportedNamespace NB callback

This callback replaces getVendorNamespace(). Fix nativeloader
to use NativeBridgeGetExportedNamespace instead of
NativeBridgeGetVendorNamespace.

Bug: http://b/121248172
Bug: http://b/121372395
Test: make
Change-Id: I8fa2081e37815f6f65490c9536bed0687b7f1e77
4 files changed