Low: pgsql: PostgreSQL 9.3 compatibility for unix_socket_directories

This patch changes procedure for setting default value of the "OCF_RESKEY_socketdir" based on the "unix_socket_directory" in the PostgreSQL 9.3 or higher.

The PostgreSQL 9.3 allows multiple socket directories and configuration parameter name the "unix_socket_directory" has been changed to the "unix_socket_directories".

Most inportant thing is that pgsql RA does not know how many directories are defined and which directory is used for psql command.

Thus, user must be set the "socketdir" parameter if user set the "unix_socket_directories" in the postgresql.conf.

If the "unix_socket_directories" is not configured in the postgresql.conf, there is no change from the PostgreSQL 9.2 or lower.