Adjust Docker file and rpmbuild.sh for new rpm name.

Also restructure Dockerfile rpmbuild.sh. Now
pgpool-II-33-pg92/rpmbuild.sh and pgpool-II-33-pg93/rpmbuild.sh are
identical. Also pgpool-II-33-pg92/Dockerfile and
pgpool-II-33-pg93/Dockerfile are almost same except the version number
ENV command.