Initialize driver_uuid with build id.

This was giving garbage before, so UUIDs between two instances of the
same driver never match and CTS tests for sharing textures fail. The
code for retrieving the build ID from the ELF works on Fuchsia, so we
should be using it.

MA-319 #done

Change-Id: Id180a580d6ce1ab970080d227c9d9275484d21d9
4 files changed