changed  rmp -i to yum localinstall to keep db in sync
Don't hard-code x86_64. use yum localinstall instead of rpm.

Architecture should be automatic on CentoOS6, so script should be compatible with i686 too.
yum localinstall ensures package installation is recorded in the yum database.
Add unzip, disable mod_fastcgi and PYTHONPATH.

mod_fastcgi shouldn't be needed for nginx.
Ice python modules are in system path, so shouldn't need PYTHONPATH
Enable md5 authentication for postgres