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/lib/Driver/ArgList.cpp b/lib/Driver/ArgList.cpp
index 6f7cbb6..ca9b944 100644
--- a/lib/Driver/ArgList.cpp
+++ b/lib/Driver/ArgList.cpp
@@ -136,7 +136,7 @@
 }
 
 int ArgList::getLastArgIntValue(OptSpecifier Id, int Default,
-                                clang::Diagnostic &Diags) const {
+                                clang::DiagnosticsEngine &Diags) const {
   int Res = Default;
 
   if (Arg *A = getLastArg(Id)) {