#3046 log: clean up number of older log file without closing current log file

[Canh Truong]

Remove some log files after the priod time but the current of log file is not closed.
It is useful if user doesn't want the log file exist after some days. The current log file may be empty or don't have too much log records. It just remove the older log files and don't need to close current log file.

Improve the enhancement of ticket #3022

[Canh Truong]

commit 68efc6010fda86d62300a687bbd8c52cba232479 (HEAD -> develop, origin/develop, ticket-3046)
Author: Canh Van Truong canh.v.truong@dektech.com.au
Date: Tue Jun 18 18:14:08 2019 +0700

log: Delete the older file without closing current log file via admin operation [#3046]

Improve the enhancement of ticket #3022, the user can rotate (delete) older log
files without closing current log file.

LOG add new parameter (numberOfFilesToRemove) to admin op command with id = 2.
 - If parameter exists, LOGD remove number of older file base on parameter value
 - If parameter is omitted, LOGD rotates log file normally. (closing current log
file, rotate log file if needed, create new log file)

This helps to avoid creating empty log file or small log file size