Return an ErrorOr<Binary *> from createBinary.

I did write a version returning ErrorOr<OwningPtr<Binary> >, but it is too
cumbersome to use without std::move. I will keep the patch locally and submit
when we switch to c++11.

llvm-svn: 199326
diff --git a/llvm/tools/llvm-readobj/llvm-readobj.cpp b/llvm/tools/llvm-readobj/llvm-readobj.cpp
index 2d9f3e5..916c658 100644
--- a/llvm/tools/llvm-readobj/llvm-readobj.cpp
+++ b/llvm/tools/llvm-readobj/llvm-readobj.cpp
@@ -260,11 +260,12 @@
   }
 
   // Attempt to open the binary.
-  OwningPtr<Binary> Binary;
-  if (error_code EC = createBinary(File, Binary)) {
+  ErrorOr<Binary *> BinaryOrErr = createBinary(File);
+  if (error_code EC = BinaryOrErr.getError()) {
     reportError(File, EC);
     return;
   }
+  OwningPtr<Binary> Binary(BinaryOrErr.get());
 
   if (Archive *Arc = dyn_cast<Archive>(Binary.get()))
     dumpArchive(Arc);