Prevent at compile time converting from Error::success() to Expected<T>

This would trigger an assertion at runtime otherwise.

Differential Revision: https://reviews.llvm.org/D26482

llvm-svn: 286562
diff --git a/lldb/source/Interpreter/OptionValueString.cpp b/lldb/source/Interpreter/OptionValueString.cpp
index b5ce38c..e61ead0 100644
--- a/lldb/source/Interpreter/OptionValueString.cpp
+++ b/lldb/source/Interpreter/OptionValueString.cpp
@@ -133,7 +133,7 @@
       return error;
   }
   m_current_value.assign(value);
-  return Error::success();
+  return Error();
 }
 
 Error OptionValueString::AppendToCurrentValue(const char *value) {
@@ -148,5 +148,5 @@
     } else
       m_current_value.append(value);
   }
-  return Error::success();
+  return Error();
 }