Fix test and add missing return for llvm-lto2 error case

Summary:
This test was missing the target triple.
Once I fixed that, the case with the invalid character error stopped
returning 1 from llvm-lto2 and the test reported a failure. Fixed by
adding the missing return from llvm-lto2. Apparently we were failing
when we eventually tried to get the target.

Reviewers: pcc

Subscribers: mehdi_amini, llvm-commits

Differential Revision: https://reviews.llvm.org/D30585

llvm-svn: 297173
diff --git a/llvm/test/tools/llvm-lto2/errors.ll b/llvm/test/tools/llvm-lto2/errors.ll
index 25c0543..bc1f767 100644
--- a/llvm/test/tools/llvm-lto2/errors.ll
+++ b/llvm/test/tools/llvm-lto2/errors.ll
@@ -10,5 +10,6 @@
 ; ERR4: invalid resolution: foo
 
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
 
 @foo = global i32 0