Fix bogus diagnostic format string.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@96978 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/CIndex/CIndexCodeCompletion.cpp b/tools/CIndex/CIndexCodeCompletion.cpp
index b646474..3b7674e 100644
--- a/tools/CIndex/CIndexCodeCompletion.cpp
+++ b/tools/CIndex/CIndexCodeCompletion.cpp
@@ -330,7 +330,7 @@
         AllArgs += *I;
     }
     
-    Diags->Report(diag::err_fe_clang) << AllArgs << ErrMsg;
+    Diags->Report(diag::err_fe_invoking) << AllArgs << ErrMsg;
   }
 
   // Parse the resulting source file to find code-completion results.