Fix off-by-one printing month in logging code

The field 'mon' in 'struct tm' gives months 0-11, where as
humans tend to expect months 1-12. Thus the month number
needing adjusting by 1

* src/util/logging.c: Use human friendly month number

src/util/logging.c

@@ -628,6 +628,7 @@ virLogFormatTimestamp(void)
     gettimeofday(&cur_time, NULL);
     localtime_r(&cur_time.tv_sec, &time_info);
     time_info.tm_year += 1900;
+    time_info.tm_mon += 1;
 
     if (virAsprintf(&str, "%4d-%02d-%02d %02d:%02d:%02d.%03d",
                     time_info.tm_year, time_info.tm_mon, time_info.tm_mday,