Use 'free' to release PerIDCache since it was allocated using calloc().

llvm-svn: 60556
diff --git a/clang/lib/Lex/PTHLexer.cpp b/clang/lib/Lex/PTHLexer.cpp
index 63f2722..85d009b 100644
--- a/clang/lib/Lex/PTHLexer.cpp
+++ b/clang/lib/Lex/PTHLexer.cpp
@@ -244,7 +244,7 @@
 PTHManager::~PTHManager() {
   delete Buf;
   delete (PTHFileLookup*) FileLookup;
-  delete [] (IdentifierInfo**) PerIDCache;
+  assert(PerIDCache); free(PerIDCache);
 }
 
 PTHManager* PTHManager::Create(const std::string& file, Preprocessor& PP) {