[llvm-readobj] - Remove `error(llvm::Expected<T> &&E)`

This is a bit strange method. It works like a unwrapOrError,
but named error. It does not report an Input name.
I removed it.

Differential revision: https://reviews.llvm.org/D66000

llvm-svn: 368430
diff --git a/llvm/tools/llvm-readobj/WasmDumper.cpp b/llvm/tools/llvm-readobj/WasmDumper.cpp
index 041a9a1..2ffc74b 100644
--- a/llvm/tools/llvm-readobj/WasmDumper.cpp
+++ b/llvm/tools/llvm-readobj/WasmDumper.cpp
@@ -90,7 +90,7 @@
   StringRef SymName;
   symbol_iterator SI = Reloc.getSymbol();
   if (SI != Obj->symbol_end())
-    SymName = error(SI->getName());
+    SymName = unwrapOrError(Obj->getFileName(), SI->getName());
 
   bool HasAddend = false;
   switch (RelocType) {