Produce a hidden symbol for zed in

  struct HIDDEN foo {
  };
  template <class P>
  struct bar {
  };
  template <>
  struct HIDDEN bar<foo> {
    DEFAULT static void zed();
  };
  void bar<foo>::zed() {
  }

Before we would produce a hidden symbol in

  struct HIDDEN foo {
  };
  template <class P>
  struct bar {
  };
  template <>
  struct bar<foo> {
    DEFAULT static void zed();
  };
  void bar<foo>::zed() {
  }

But adding HIDDEN to the specialization would cause us to produce a default
symbol.

llvm-svn: 157206
diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp
index d31cf0f..8bc9eb3 100644
--- a/clang/lib/AST/Decl.cpp
+++ b/clang/lib/AST/Decl.cpp
@@ -163,7 +163,7 @@
 }
 
 static bool shouldConsiderTemplateLV(const ClassTemplateSpecializationDecl *d) {
-  return !d->hasAttr<VisibilityAttr>();
+  return !d->hasAttr<VisibilityAttr>() || d->isExplicitSpecialization();
 }
 
 static LinkageInfo getLVForNamespaceScopeDecl(const NamedDecl *D,