perf record: Reset event name when falling back to cpu-clock

perf-record defaults to the H/W cycles event and if it is not supported
falls back to cpu-clock. Reset the event name as well.
Signed-off-by: David Ahern <dsahern@gmail.com>
Link: http://lkml.kernel.org/r/1336495811-58461-1-git-send-email-dsahern@gmail.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-record.c

@@ -256,6 +256,10 @@ static void perf_record__open(struct perf_record *rec)
 						    "trying to fall back to cpu-clock-ticks\n");
 				attr->type = PERF_TYPE_SOFTWARE;
 				attr->config = PERF_COUNT_SW_CPU_CLOCK;
+				if (pos->name) {
+					free(pos->name);
+					pos->name = NULL;
+				}
 				goto try_again;
 			}