libvirt.tests: libvirt.tests: add test cases for libivirtd access via UNIX, SSH, TLS and TCP transports

Signed-off-by: Alex Jia <ajia@redhat.com>
Merge pull request #220 from chuanchang/remote_access

libvirt.tests: add test cases for libivirtd access via UNIX, SSH, TLS and TCP transports