abitool: add proper error handling for abidiff

The handling of the various error codes emitted by abidiff was
incomplete. Fix that by handling the issues the same way they are
generated.

Change-Id: I626212aa0a8817bc2bfa9168f71bfd5e30c415cd
Signed-off-by: Matthias Maennich <maennich@google.com>
1 file changed