Pass a std::unique_ptr& to the create??? methods is lib/Object.

This makes the buffer ownership on error conditions very natural. The buffer
is only moved out of the argument if an object is constructed that now
owns the buffer.

llvm-svn: 211546
diff --git a/llvm/tools/llvm-objdump/MachODump.cpp b/llvm/tools/llvm-objdump/MachODump.cpp
index 21c4c96..74fdfef 100644
--- a/llvm/tools/llvm-objdump/MachODump.cpp
+++ b/llvm/tools/llvm-objdump/MachODump.cpp
@@ -203,7 +203,7 @@
   }
 
   std::unique_ptr<MachOObjectFile> MachOOF(static_cast<MachOObjectFile *>(
-      ObjectFile::createMachOObjectFile(Buff.release()).get()));
+      ObjectFile::createMachOObjectFile(Buff).get()));
 
   DisassembleInputMachO2(Filename, MachOOF.get());
 }
@@ -293,7 +293,7 @@
         errs() << "llvm-objdump: " << Filename << ": " << ec.message() << '\n';
         return;
       }
-      DbgObj = ObjectFile::createMachOObjectFile(Buf.release()).get();
+      DbgObj = ObjectFile::createMachOObjectFile(Buf).get();
     }
 
     // Setup the DIContext