toolchain-shar-extract: Correct environment-setup script names for multilib
Currently a lib32-core-image-* SDK prints an incorrect environment-setup-*
file name when installing the SDK. Instead of printing the wrong thing, list
the environment setup files present in the SDK.
As it happens this fixes the message printed with buildtools-tarball too
which someone reported to me about the same time as I finished this patch!
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
