libguestfs.tests: Add test module for partition operations.

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>
libguestfs.tests: Add test module for volume operations.

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>
libguestfs.tests: Add test module for virt_inspect_operations.

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>
Merge pull request #35 from yumingfei/virt_part_oper

libguestfs.tests: Add testcases.