Revert r194865 and r194874.

This change is incorrect. If you delete virtual destructor of both a base class
and a subclass, then the following code:
  Base *foo = new Child();
  delete foo;
will not cause the destructor for members of Child class. As a result, I observe
plently of memory leaks. Notable examples I investigated are:
ObjectBuffer and ObjectBufferStream, AttributeImpl and StringSAttributeImpl.

llvm-svn: 194997

llvm/lib/Support/ErrorHandling.cpp

@@ -17,7 +17,6 @@
 #include "llvm/ADT/Twine.h"
 #include "llvm/Config/config.h"
 #include "llvm/Support/Debug.h"
-#include "llvm/Support/ErrorOr.h"
 #include "llvm/Support/Signals.h"
 #include "llvm/Support/Threading.h"
 #include "llvm/Support/raw_ostream.h"
@@ -120,4 +119,3 @@ void LLVMInstallFatalErrorHandler(LLVMFatalErrorHandler Handler) {
 void LLVMResetFatalErrorHandler() {
   remove_fatal_error_handler();
 }
-