Fix Clang 3.7 build issue in VS 2015 Update 1

VS 2015 Update 1 adds support for 'Clang 3.7 with Microsoft CodeGen'.

This fixes these errors when using Clang 3.7 in VS2015:

compiler\translator\ASTMetadataHLSL.cpp(69,10): error : 'visitLoop' overrides a member function but is not marked 'override' [-Werror,-Winconsistent-missing-override]
compiler\translator\ASTMetadataHLSL.cpp(75,10): error : 'visitSelection' overrides a member function but is not marked 'override' [-Werror,-Winconsistent-missing-override]
compiler\translator\ASTMetadataHLSL.cpp(336,10): error : 'visitLoop' overrides a member function but is not marked 'override' [-Werror,-Winconsistent-missing-override]

Change-Id: Ia9c3029eb2966132827596b55ad9afce34b6f19c
Reviewed-on: https://chromium-review.googlesource.com/317732
Tryjob-Request: Austin Kinross <aukinros@microsoft.com>
Tested-by: Austin Kinross <aukinros@microsoft.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
diff --git a/src/compiler/translator/ASTMetadataHLSL.cpp b/src/compiler/translator/ASTMetadataHLSL.cpp
index cc21a00..31bfae9 100644
--- a/src/compiler/translator/ASTMetadataHLSL.cpp
+++ b/src/compiler/translator/ASTMetadataHLSL.cpp
@@ -66,13 +66,13 @@
         }
     }
 
-    bool visitLoop(Visit visit, TIntermLoop *loop)
+    bool visitLoop(Visit visit, TIntermLoop *loop) override
     {
         visitControlFlow(visit, loop);
         return true;
     }
 
-    bool visitSelection(Visit visit, TIntermSelection *selection)
+    bool visitSelection(Visit visit, TIntermSelection *selection) override
     {
         visitControlFlow(visit, selection);
         return true;
@@ -333,7 +333,7 @@
         ASSERT(mNestedDiscont == (mMetadata->mCalledInDiscontinuousLoop ? 1 : 0));
     }
 
-    bool visitLoop(Visit visit, TIntermLoop *loop)
+    bool visitLoop(Visit visit, TIntermLoop *loop) override
     {
         bool isDiscontinuous = mMetadata->mDiscontinuousLoops.count(loop) > 0;