Use std::string for the identifier consistently

python/dune/perftool/pdelab/localoperator.py

@@ -579,7 +579,7 @@ class TimerMethod(ClassMember):
         assert(knl is not None)
 
         content = ["template <typename Stream>",
-                   "void dump_timers(Stream& {}, const char* {}, bool {})".format(os, ident, reset),
+                   "void dump_timers(Stream& {}, std::string {}, bool {})".format(os, ident, reset),
                    "{"]
         dump_timers = [i for i in retrieve_cache_items(condition='dump_timers')]
         content.extend(map(lambda x: '  ' + x, dump_timers))