Add testcase virsh_net_edit

New files:
network/virsh_net_edit.cfg
network/virsh_net_edit.py

Signed-off-by: Guannan Ren <gren@redhat.com>
snapshot_disk: Perform xml save/restore

For some reason this test failed in a long run, subsequent tests failed
because improper cleanup left a snapshot in the xml, but not in the file
system resulting in the next test(s) failing to find the file.
Add new test for domdisplay
Merge pull request #32 from kylazhang/domdisplay

Add new test for domdisplay
Merge pull request #44 from Guannan-Ren/net-edit

Add virsh command testcase virsh_net_edit
libvirt.tests: Fix pep8 problems for net_edit test.

Signed-off-by: Yu Mingfei <yumingfei@cn.fujitsu.com>
Merge pull request #59 from jferlan/snapshot_disk

snapshot_disk: Perform xml save/restore
Fix test name

Looks like this test was missed - change to use just 'run()' as the
entry point... Message in debug.log is:

"Legacy test entry point function name found..."
Merge pull request #68 from jferlan/dompmsuspend

Fix test name
Add test for domblkerror

Signed-off-by: Kyla Zhang <weizhan@redhat.com>