Fix a tiny goof in the Driver's logic which caused the explicit presence
of -fexceptions to disably C++ exceptions. The correct code was in the
ObjC branch, this just mirrors that logic on the C++ side of things.
Thanks to John Wiegley for pointing this out.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@126640 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index 475b904..6f37365 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -845,7 +845,7 @@
                                  options::OPT_fno_exceptions)) {
       if (A->getOption().matches(options::OPT_fcxx_exceptions))
         CXXExceptionsEnabled = true;
-      else
+      else if (A->getOption().matches(options::OPT_fno_cxx_exceptions))
         CXXExceptionsEnabled = false;
     }