Remove old restriction description which is no longer true.

Following descriptions are removed ([pgpool-general: 2815].

>> pgpool-II does not support pg_hba.conf-like access controls. If TCP/IP
> connections are enabled, pgpool-II accepts all the connections from any
> host.

>> "hostssl" connection type is not supported
Fix return type of text_to_lsn() function
Fix possible pgpool-recovery crash when used with pre-3.4 environment.

Between 3.3 and 3.4 the number of parameters are changed from 3 to
4. Before pgpool-recovery checks the number of arguments by using
PointerGetDatum(PG_GETARG_TEXT_P(3)) returns null or not.  This is
wrong and now we use PG_NARGS() macro.

Also pgpool-recovery's Makefile now installs pgpool_recovery--1.1.sql,
rather than pgpool_recovery--1.0.sql to deal with the changes of
number of arguments.
Allow pgpool-recovery to accept pre-3.4 style fewer arguments.

It is nice for pre/post 3.4 mixing environemnt to accept pre-3.4 style
fewer arguments, rather than throwing an error and abort.