Bug Fix of install_server.sh

Change LOG:
1. Less -e (in case of '!`which chkconfig`'), the generated redis start up script isn't runable. 
2. '!`which chkconfig`' may cause error in CentOS. Change this code to '! `which chkconfig`' can correct it.

Commited by Yin Mingjun (yinmingjunn@gmail.com)
2014-02-21