Rename Diagnostic to DiagnosticsEngine as per issue 5397


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@140478 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/libclang/CIndexDiagnostic.cpp b/tools/libclang/CIndexDiagnostic.cpp
index db71a76..26f69b0 100644
--- a/tools/libclang/CIndexDiagnostic.cpp
+++ b/tools/libclang/CIndexDiagnostic.cpp
@@ -182,11 +182,11 @@
     return CXDiagnostic_Ignored;
 
   switch (StoredDiag->Diag.getLevel()) {
-  case Diagnostic::Ignored: return CXDiagnostic_Ignored;
-  case Diagnostic::Note:    return CXDiagnostic_Note;
-  case Diagnostic::Warning: return CXDiagnostic_Warning;
-  case Diagnostic::Error:   return CXDiagnostic_Error;
-  case Diagnostic::Fatal:   return CXDiagnostic_Fatal;
+  case DiagnosticsEngine::Ignored: return CXDiagnostic_Ignored;
+  case DiagnosticsEngine::Note:    return CXDiagnostic_Note;
+  case DiagnosticsEngine::Warning: return CXDiagnostic_Warning;
+  case DiagnosticsEngine::Error:   return CXDiagnostic_Error;
+  case DiagnosticsEngine::Fatal:   return CXDiagnostic_Fatal;
   }
 
   llvm_unreachable("Invalid diagnostic level");