When viewing logs in utilities, filenames should be limited the same as clog

[netniV]

Go to system utilities - Log Administration page, check File drop down list, it can not only show cacti.log, but also show files named begin with cacti.log.xxx that I created, thus the gz file can not display -- Failed.

Cacti 1.2.3
FF
rhel7 x64

[netniV]

This is the bug fix side of #2711 pointed out by @ddb4github and originally reportd by @yingbaiibm