fixed a printf argument in the new logging stuff
diff --git a/aos/common/logging/logging_impl.cc b/aos/common/logging/logging_impl.cc
index 64696dc..147d6ba 100644
--- a/aos/common/logging/logging_impl.cc
+++ b/aos/common/logging/logging_impl.cc
@@ -113,7 +113,7 @@
void PrintMessage(FILE *output, const LogMessage &message) {
fprintf(output, "%s(%"PRId32")(%05"PRIu16"): %s at"
" %010"PRId32".%09"PRId32"s: %s",
- message.name, message.source, message.sequence,
+ message.name, static_cast<int32_t>(message.source), message.sequence,
log_str(message.level), message.seconds, message.nseconds,
message.message);
}