High: nfsserver.sh: add an optional option for the rpc.statd listening port

Signed-off-by: Niels de Vos <ndevos@redhat.com>
Low: pgsql: add a parameter and a function for using cascade replication.

Add "cascade" parameter and "is_cascade()" function.
Cascade is replication between 3 or more PostgreSQL in series.
If cascade parameter is "true", it is possible to use cascade replication.
is_cascade function judges the cascade is "true" or "false".
Low: pgsql: add another way of description of master_ip for cascade replication.

If cascade is true, each node has a parent and a ip address which connect to.
the way is write the sets of "node name:parent's IP address" for each node separated with a space.
If cascade is false, the description of master_ip is the same as conventional.
High: pgsql: add a new attribute as $PGSQL_CHILDREN and attribute value as HS:cascade.

On the existing pgsql RA, all slave nodes are master node's children.
But in cascade replication, it is possible that a slave node have it's children.
Therefor, it is necessary to manage that a node is whose child, and it is specified by $PGSQL_CHILDREN.
In addition, when the 3 or more nodes are on cascade, HS:cascade is shown instead of HS:async.
Low: pgsql: add validation checks for cascade replication.