odbc: Remove options that are no longer applicable.

The pooling, shared_connection, limit, and idlecheck options
are no longer used in res_odbc.

ASTERISK-26389

Change-Id: I2fde7b467d01f9d1c82cc0a339bb4f7e1dd6bbe6

configs/samples/res_odbc.conf.sample

@@ -38,19 +38,6 @@ pre-connect => yes
 ; record.  The default is "select 1".
 ;sanitysql => select 1
 ;
-; On some databases, the connection times out and a reconnection will be
-; necessary.  This setting configures the amount of time a connection
-; may sit idle (in seconds) before a reconnection will be attempted.
-;idlecheck => 3600
-;
-; Should we use a single connection for all queries?  Most databases will
-; allow sharing the connection, though Sybase and MS SQL Server will not.
-;share_connections => yes
-;
-; If we aren't sharing connections, what is the maximum number of connections
-; that we should attempt?
-;limit => 5
-;
 ; The maximum number of connections to have open at any given time.
 ; This defaults to 1 and it is highly recommended to only set this higher
 ; if using a version of UnixODBC greater than 2.3.1.