Simplify and rename variable.

std::error_code can represent success, so we don't need a
Optional<std::error_code>.

Rename the variable to avoid confusion with the type Error.

llvm-svn: 318111
diff --git a/llvm/lib/Support/LockFileManager.cpp b/llvm/lib/Support/LockFileManager.cpp
index ad749e0..3b5a8b5 100644
--- a/llvm/lib/Support/LockFileManager.cpp
+++ b/llvm/lib/Support/LockFileManager.cpp
@@ -261,16 +261,16 @@
   if (Owner)
     return LFS_Shared;
 
-  if (Error)
+  if (ErrorCode)
     return LFS_Error;
 
   return LFS_Owned;
 }
 
 std::string LockFileManager::getErrorMessage() const {
-  if (Error) {
+  if (ErrorCode) {
     std::string Str(ErrorDiagMsg);
-    std::string ErrCodeMsg = Error->message();
+    std::string ErrCodeMsg = ErrorCode.message();
     raw_string_ostream OSS(Str);
     if (!ErrCodeMsg.empty())
       OSS << ": " << ErrCodeMsg;