clang-import-test: fix build with clang-3.8

clang-3.8 complains that constructor for '...' must explicitly
initialize the const object. Newer clangs and gcc seem to be fine with
this, but explicitly initializing the variable does not hurt.

llvm-svn: 327383
diff --git a/clang/tools/clang-import-test/clang-import-test.cpp b/clang/tools/clang-import-test/clang-import-test.cpp
index e2cf7d8..d218d41 100644
--- a/clang/tools/clang-import-test/clang-import-test.cpp
+++ b/clang/tools/clang-import-test/clang-import-test.cpp
@@ -245,7 +245,7 @@
   ASTContext &getASTContext() { return CI->getASTContext(); }
   FileManager &getFileManager() { return CI->getFileManager(); }
   const OriginMap &getOriginMap() {
-    static const OriginMap EmptyOriginMap;
+    static const OriginMap EmptyOriginMap{};
     if (ExternalASTSource *Source = CI->getASTContext().getExternalSource())
       return static_cast<ExternalASTMerger *>(Source)->GetOrigins();
     return EmptyOriginMap;