fix printing out log timestamps

It was fixed-width before, but left-padded with zeros. This got a lot
worse once I fixed there not being enough of them. It now uses spaces on
the right instead.

Change-Id: If1ecc196c5801b5ca4f218bffda61a23fa5c68c1
diff --git a/aos/common/logging/logging_printf_formats.h b/aos/common/logging/logging_printf_formats.h
index 0bf253c..f7ab7bd 100644
--- a/aos/common/logging/logging_printf_formats.h
+++ b/aos/common/logging/logging_printf_formats.h
@@ -10,7 +10,7 @@
 // logging_impl.cc.
 
 #define AOS_TIME_FORMAT \
-  "%010" PRId32 ".%0" STRINGIFY(AOS_TIME_NSECONDS_DIGITS) PRId32 "s"
+  "%010" PRId32 ".%-" STRINGIFY(AOS_TIME_NSECONDS_DIGITS) PRId32 "s"
 #define AOS_TIME_ARGS(sec, nsec)                      \
   sec, (nsec + (AOS_TIME_NSECONDS_DENOMINATOR / 2)) / \
       AOS_TIME_NSECONDS_DENOMINATOR