shared.cfg: Add remote host parameters to base.cfg.

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>
libvirt.tests: Remove remote host parameters.

Uniform remote parameters to base.cfg.Then there is no need
to configure in every 'test'.cfg.

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>