The test used to import ../callback. I forget why that ever worked,
but it probably had something to do with the shared libraries we used
to use with SWIG. It doesn't work today.
Change-Id: Ib83d6c398aa46bf2fc66320b47b6e6d9897ee0b7
Reviewed-on: https://go-review.googlesource.com/7004
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Also add the action's object directory to the list of
directories we use to find SWIG shared libraries.
Fixes#6521.
R=golang-dev, minux.ma
CC=golang-dev
https://golang.org/cl/14369043
