trace_processor: fix build

Change-Id: Ic45bef20ce767815f883901de69283f3f6d3dd9b
diff --git a/src/trace_processor/slice_tracker.cc b/src/trace_processor/slice_tracker.cc
index 46e5c33..45e6c17 100644
--- a/src/trace_processor/slice_tracker.cc
+++ b/src/trace_processor/slice_tracker.cc
@@ -67,7 +67,7 @@
                               uint32_t atrace_tid) {
   uint32_t actual_tid = ftrace_to_atrace_pid_[ftrace_tid];
   if (atrace_tid != 0 && atrace_tid != actual_tid) {
-    PERFETTO_DLOG("Mismatched atrace pid %u and looked up pid %u", , atrace_tid,
+    PERFETTO_DLOG("Mismatched atrace pid %u and looked up pid %u", atrace_tid,
                   actual_tid);
   }
   if (actual_tid == 0)