Unable to start mysql
I found my answer and I want to laugh on myself... What a silly mistake I did!
Sharing this solution so that others can save their time.
I just prefix sudo command in the below statement and mysql started.

$ sudo /etc/rc.d/init.d/mysql start


Input password:
Starting MySQL.
I checked and found that MySQL is running by issuing below command:

$ mysqladmin -u root -pjoomla1 ping


mysqld is alive