The use of a macro for PGSVCNAME is necessary so we can have a single point to control (stop/start/initdb) Postgresql even though across vendors the name of the service is different.
postgresql
postgresql93
postgresql-9.3

The substitution in the postgresql-9.3 service script is needed because the init script over-ride the port that is also set in the /var/lib/pgsql/9.3/data/.postgresql.conf file. Setting both to port 5439 instead of 5432 (the default) avoids a port conflict.