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>
pool_create: Resolve test errors

Originally posted to virt-test before the commit as PR 1236:

https://github.com/autotest/virt-test/pull/1236

This replaces and resolves issues mentioned from review. The main
difference between this version and the last one posted previously
is that the code now handles the transient 'default' storage pool
not being started prior to the test being run in the "error" case.
I also cleaned up and commented more the finally logic.
find_storage_pool_sources_as: Check for required utilities

In order to run the iscsi and logical tests, the 'tgtadm' and
'iscsiadm' utilities must be installed; otherwise, tests fail.
Add check and skip if not installed.
Add try/except for login_iscsi and create_vg failure

Add a try/except for login_iscsi or create_vg failure.  If the login_iscsi
fails, then we leave with the iscsiadm still logged in if the creation
of the vg fails.  If either fails, then use the exception to propagate
the error.
libvirt-test: Add test cases for nodedev-list

Test command: nodedev-list [--tree] [--cap <string>]

1) Run nodedev-list command and check return code.
2) If `cap_option == one`, results are also compared
   with devices get from sysfs.

Signed-off-by: Hao Liu <hliu@redhat.com>
libvirt: Fix nodedev_list in nodedev_create_destroy

1) Change nodedev_list according to change of API in virsh.py.
   There are two references of old nodedev_list API, one is fixed
   in this commit, and another used in nodedev_reset is no need to
   fix.

2) We don't need to start VM when testing host node devices. this
   will save us a little time.

Signed-off-by: Hao Liu <hliu@redhat.com>
libvirt: Fix nodedev_list in pci_passthrough

1) Change nodedev_list according to change of API in virsh.py.

Signed-off-by: Hao Liu <hliu@redhat.com>