File set-revision.patch of Package llvm7

Index: cfe-5.0.0rc1.src/lib/Basic/Version.cpp
===================================================================
--- cfe-5.0.0rc1.src/lib/Basic/Version.cpp.orig
+++ cfe-5.0.0rc1.src/lib/Basic/Version.cpp
@@ -72,19 +72,11 @@ std::string getLLVMRepositoryPath() {
 }
 
 std::string getClangRevision() {
-#ifdef SVN_REVISION
   return SVN_REVISION;
-#else
-  return "";
-#endif
 }
 
 std::string getLLVMRevision() {
-#ifdef LLVM_REVISION
   return LLVM_REVISION;
-#else
-  return "";
-#endif
 }
 
 std::string getClangFullRepositoryVersion() {