xmlrpcTests: Mount configfs automatically

In some systems such as Ubuntu, configfs is not mounted by default.

In this patch, configfs is mounted automatically for iscsi tests.

Change-Id: I2c507dc8e7cc8e48a9b0ee46ba958ec58b0bb91b
Signed-off-by: Zhou Zheng Sheng <zhshzhou@linux.vnet.ibm.com>
Reviewed-on: http://gerrit.ovirt.org/17811
Reviewed-by: Dan Kenigsberg <danken@redhat.com>