How to manually delete a server pool on Oracle VM 2.1.2

As no "Force remove" feature in Oracle VM 2.1.2, one has to manually delete a server pool when failed to delete it  with Oracle VM manager.   On Oracle VM manger machine:
1, Setting DB environment;
- # export ORACLE_SID=XE
- # export ORACLE_HOME=/usr/lib/oracle/xe/app/oracle/product/10.2.0/server
- # export PATH=$PATH:$ORACLE_HOME/bin

2,
# sqlplus OVS/oracle@xe
....
SQL> select SITE_NAME,SITE_ID from OVS_SITE;

SITE_NAME
--------------------------------------------------------------------------------
SITE_ID
----------
ovm_pool
30

SQL> delete from OVS_SITE where SITE_ID=30;

1 row deleted.
SQL> select SITE_NAME,SITE_ID from OVS_SITE where SITE_ID=30;

no rows selected