zero-pad date string output.

2019/ 5/ 9 21:18:01:710 notice -> 2019/05/09 21:18:01:710 notice

Change-Id: I8ed932a0d6f5e6ce29ab6428f0f01221d0a6ae34
Signed-off-by: Paul Vinciguerra <pvinci@vinciconsulting.com>
diff --git a/src/vppinfra/unix-formats.c b/src/vppinfra/unix-formats.c
index c447329..7059686 100644
--- a/src/vppinfra/unix-formats.c
+++ b/src/vppinfra/unix-formats.c
@@ -812,11 +812,11 @@
 	  break;
 	case 'm':
 	  what = tm->tm_mon + 1;
-	  what_fmt = "%2d";
+	  what_fmt = "%02d";
 	  break;
 	case 'd':
 	  what = tm->tm_mday;
-	  what_fmt = "%2d";
+	  what_fmt = "%02d";
 	  break;
 	case 'H':
 	  what = tm->tm_hour;