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

# for UNIX test cases
```
$ ./run -t libvirt --test type_specific.io-github-autotest-libvirt.virsh.remote_with_unix --no-downloads --keep-image
SETUP: PASS (0.34 s)
DATA DIR: /var/lib/virt_test
DEBUG LOG: /tmp/virt-test/logs/run-2014-06-27-16.15.48/debug.log
TESTS: 14
(1/14) type_specific.io-github-autotest-libvirt.virsh.remote_with_unix.positive_testing.default_unix_config: PASS (12.90 s)
(2/14) type_specific.io-github-autotest-libvirt.virsh.remote_with_unix.positive_testing.readonly: PASS (13.20 s)
(3/14) type_specific.io-github-autotest-libvirt.virsh.remote_with_unix.positive_testing.customized_unix_sock_dir: PASS (74.16 s)
(4/14) type_specific.io-github-autotest-libvirt.virsh.remote_with_unix.positive_testing.default_config_and_start_vm: PASS (17.88 s)
(5/14) type_specific.io-github-autotest-libvirt.virsh.remote_with_unix.positive_testing.allow_sasl_users: PASS (90.07 s)
(6/14) type_specific.io-github-autotest-libvirt.virsh.remote_with_unix.positive_testing.socket_access_controls: PASS (14.36 s)
(7/14) type_specific.io-github-autotest-libvirt.virsh.remote_with_unix.positive_testing.socket_with_auth_conf: PASS (76.76 s)
(8/14) type_specific.io-github-autotest-libvirt.virsh.remote_with_unix.positive_testing.socket_with_polkit_and_acl_control: PASS (21.74 s)
(9/14) type_specific.io-github-autotest-libvirt.virsh.remote_with_unix.positive_testing.socket_with_polkit_rw: PASS (18.77 s)
(10/14) type_specific.io-github-autotest-libvirt.virsh.remote_with_unix.negative_testing.no_allowed_sasl_user: PASS (90.55 s)
(11/14) type_specific.io-github-autotest-libvirt.virsh.remote_with_unix.negative_testing.allow_sasl_user_with_readonly: PASS (85.51 s)
(12/14) type_specific.io-github-autotest-libvirt.virsh.remote_with_unix.negative_testing.readonly_without_auth: PASS (12.77 s)
(13/14) type_specific.io-github-autotest-libvirt.virsh.remote_with_unix.negative_testing.socket_access_controls: PASS (14.64 s)
(14/14) type_specific.io-github-autotest-libvirt.virsh.remote_with_unix.negative_testing.socket_with_polkit_ro: PASS (13.98 s)
TOTAL TIME: 557.40 s (09:17)
TESTS PASSED: 14
TESTS FAILED: 0
SUCCESS RATE: 100.00 %
```

# for SSH test cases
```
$ ./run -t libvirt --test type_specific.io-github-autotest-libvirt.virsh.remote_with_ssh --no-downloads --keep-image
SETUP: PASS (0.34 s)
DATA DIR: /var/lib/virt_test
DEBUG LOG: /tmp/virt-test/logs/run-2014-06-27-16.28.26/debug.log
TESTS: 11
(1/11) type_specific.io-github-autotest-libvirt.virsh.remote_with_ssh.positive_testing.ssh_diff_libvirt_version: PASS (10.78 s)
(2/11) type_specific.io-github-autotest-libvirt.virsh.remote_with_ssh.positive_testing.ssh_static_ipv6: PASS (17.66 s)
(3/11) type_specific.io-github-autotest-libvirt.virsh.remote_with_ssh.positive_testing.gssapi_auth: PASS (9.16 s)
(4/11) type_specific.io-github-autotest-libvirt.virsh.remote_with_ssh.negative_testing.libssh2_no_auth: PASS (2.13 s)
(5/11) type_specific.io-github-autotest-libvirt.virsh.remote_with_ssh.negative_testing.ssh_no_uri_path: PASS (9.07 s)
(6/11) type_specific.io-github-autotest-libvirt.virsh.remote_with_ssh.negative_testing.ssh_read_only_mode: PASS (9.15 s)
(7/11) type_specific.io-github-autotest-libvirt.virsh.remote_with_ssh.negative_testing.ssh_no_ipv6_config: PASS (8.79 s)
(8/11) type_specific.io-github-autotest-libvirt.virsh.remote_with_ssh.negative_testing.stop_libvirtd: PASS (10.27 s)
(9/11) type_specific.io-github-autotest-libvirt.virsh.remote_with_ssh.negative_testing.incorrect_password: PASS (13.15 s)
(10/11) type_specific.io-github-autotest-libvirt.virsh.remote_with_ssh.negative_testing.ipv4_with_readonly: PASS (9.11 s)
(11/11) type_specific.io-github-autotest-libvirt.virsh.remote_with_ssh.negative_testing.ipv6_with_readonly: PASS (17.91 s)
TOTAL TIME: 117.27 s (01:57)
TESTS PASSED: 11
TESTS FAILED: 0
SUCCESS RATE: 100.00 %
```

# for TCP test cases
```
$ ./run -t libvirt --test type_specific.io-github-autotest-libvirt.virsh.remote_with_tcp --no-downloads --keep-image
SETUP: PASS (0.34 s)
DATA DIR: /var/lib/virt_test
DEBUG LOG: /tmp/virt-test/logs/run-2014-06-27-16.30.31/debug.log
TESTS: 11
(1/11) type_specific.io-github-autotest-libvirt.virsh.remote_with_tcp.positive_testing.allow_one_sasl_user: PASS (19.12 s)
(2/11) type_specific.io-github-autotest-libvirt.virsh.remote_with_tcp.positive_testing.allow_sasl_users: PASS (21.75 s)
(3/11) type_specific.io-github-autotest-libvirt.virsh.remote_with_tcp.positive_testing.customized_ipv4_tcp_port: PASS (13.88 s)
(4/11) type_specific.io-github-autotest-libvirt.virsh.remote_with_tcp.positive_testing.customized_ipv4_listen_address_with_sasl_auth: PASS (19.15 s)
(5/11) type_specific.io-github-autotest-libvirt.virsh.remote_with_tcp.positive_testing.customized_ipv6_listen_address: PASS (22.53 s)
(6/11) type_specific.io-github-autotest-libvirt.virsh.remote_with_tcp.positive_testing.customized_ipv6_tcp_port: PASS (22.47 s)
(7/11) type_specific.io-github-autotest-libvirt.virsh.remote_with_tcp.positive_testing.customized_ipv6_listen_address_with_sasl_auth: PASS (27.68 s)
(8/11) type_specific.io-github-autotest-libvirt.virsh.remote_with_tcp.negative_testing.no_allowed_sasl_user: PASS (19.30 s)
(9/11) type_specific.io-github-autotest-libvirt.virsh.remote_with_tcp.negative_testing.ipv4_with_allowed_sasl_user_readonly: PASS (19.09 s)
(10/11) type_specific.io-github-autotest-libvirt.virsh.remote_with_tcp.negative_testing.ipv6_with_readonly: PASS (22.52 s)
(11/11) type_specific.io-github-autotest-libvirt.virsh.remote_with_tcp.negative_testing.only_simpy_connect_libvirtd: PASS (0.47 s)
TOTAL TIME: 208.06 s (03:28)
TESTS PASSED: 11
TESTS FAILED: 0
SUCCESS RATE: 100.00 %
```

# for TLS test cases
```
$ ./run -t libvirt --test type_specific.io-github-autotest-libvirt.virsh.remote_with_tls --no-downloads --keep-image
SETUP: PASS (0.34 s)
DATA DIR: /var/lib/virt_test
DEBUG LOG: /tmp/virt-test/logs/run-2014-06-27-16.35.13/debug.log
TESTS: 26
(1/26) type_specific.io-github-autotest-libvirt.virsh.remote_with_tls.positive_testing.default_tls_port_and_auth_tls: PASS (25.63 s)
(2/26) type_specific.io-github-autotest-libvirt.virsh.remote_with_tls.positive_testing.no_verify_certificate: PASS (26.36 s)
(3/26) type_specific.io-github-autotest-libvirt.virsh.remote_with_tls.positive_testing.no_sanity_checks_and_no_verify: PASS (32.22 s)
(4/26) type_specific.io-github-autotest-libvirt.virsh.remote_with_tls.positive_testing.customized_tls_port: PASS (25.87 s)
(5/26) type_specific.io-github-autotest-libvirt.virsh.remote_with_tls.positive_testing.allow_one_sasl_user: PASS (31.49 s)
(6/26) type_specific.io-github-autotest-libvirt.virsh.remote_with_tls.positive_testing.allow_sasl_users: PASS (34.11 s)
(7/26) type_specific.io-github-autotest-libvirt.virsh.remote_with_tls.positive_testing.allowed_dn_list: PASS (27.10 s)
(8/26) type_specific.io-github-autotest-libvirt.virsh.remote_with_tls.positive_testing.customized_ipv4_listen_address: PASS (26.75 s)
(9/26) type_specific.io-github-autotest-libvirt.virsh.remote_with_tls.positive_testing.customized_ipv4_listen_address_with_sasl_auth: PASS (32.83 s)
(10/26) type_specific.io-github-autotest-libvirt.virsh.remote_with_tls.positive_testing.customized_ipv6_listen_address: PASS (35.10 s)
(11/26) type_specific.io-github-autotest-libvirt.virsh.remote_with_tls.positive_testing.customized_ipv6_tls_port: PASS (35.74 s)
(12/26) type_specific.io-github-autotest-libvirt.virsh.remote_with_tls.positive_testing.customized_ipv6_listen_address_with_sasl_auth: PASS (41.41 s)
(13/26) type_specific.io-github-autotest-libvirt.virsh.remote_with_tls.positive_testing.customized_x509_cert_path: PASS (26.42 s)
(14/26) type_specific.io-github-autotest-libvirt.virsh.remote_with_tls.negative_testing.only_simpy_connect_libvirtd: PASS (0.36 s)
(15/26) type_specific.io-github-autotest-libvirt.virsh.remote_with_tls.negative_testing.invalid_tls_port: PASS (24.98 s)
(16/26) type_specific.io-github-autotest-libvirt.virsh.remote_with_tls.negative_testing.tls_port_in_use: PASS (24.93 s)
(17/26) type_specific.io-github-autotest-libvirt.virsh.remote_with_tls.negative_testing.tls_listen_addr_in_use: PASS (24.04 s)
(18/26) type_specific.io-github-autotest-libvirt.virsh.remote_with_tls.negative_testing.ipv4_with_allowed_sasl_user_readonly: PASS (31.37 s)
(19/26) type_specific.io-github-autotest-libvirt.virsh.remote_with_tls.negative_testing.no_sanity_checks_without_no_verify: PASS (31.64 s)
(20/26) type_specific.io-github-autotest-libvirt.virsh.remote_with_tls.negative_testing.allowed_dn_disorder_list: PASS (27.31 s)
(21/26) type_specific.io-github-autotest-libvirt.virsh.remote_with_tls.negative_testing.allowed_dn_list_with_invalid_organization: PASS (27.15 s)
(22/26) type_specific.io-github-autotest-libvirt.virsh.remote_with_tls.negative_testing.allowed_dn_list_with_invalid_CN: PASS (27.82 s)
(23/26) type_specific.io-github-autotest-libvirt.virsh.remote_with_tls.negative_testing.verify_certificate: PASS (25.28 s)
(24/26) type_specific.io-github-autotest-libvirt.virsh.remote_with_tls.negative_testing.incorrect_ipv4_listen_address: PASS (24.26 s)
(25/26) type_specific.io-github-autotest-libvirt.virsh.remote_with_tls.negative_testing.ipv6_with_readonly: PASS (35.71 s)
(26/26) type_specific.io-github-autotest-libvirt.virsh.remote_with_tls.negative_testing.ipv6_address_unreachable: PASS (30.48 s)
TOTAL TIME: 736.55 s (12:16)
TESTS PASSED: 26
TESTS FAILED: 0
SUCCESS RATE: 100.00 %
```