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/Plugins/Process/MacOSX-Kernel/ProcessKDP.cpp b/lldb/source/Plugins/Process/MacOSX-Kernel/ProcessKDP.cpp
index 2decd29..77b9fc8 100644
--- a/lldb/source/Plugins/Process/MacOSX-Kernel/ProcessKDP.cpp
+++ b/lldb/source/Plugins/Process/MacOSX-Kernel/ProcessKDP.cpp
@@ -414,7 +414,7 @@
   return m_dyld_ap.get();
 }
 
-Error ProcessKDP::WillResume() { return Error::success(); }
+Error ProcessKDP::WillResume() { return Error(); }
 
 Error ProcessKDP::DoResume() {
   Error error;