blockcopy: Add nfs disk target testing case

Add test case with blockcopy target disk on nfs mount path.

Signed-off-by: Wayne Sun <gsun@redhat.com>
blockcopy: Add negative cases under active job

Snapshot and save will fail during active job on disk.

Signed-off-by: Wayne Sun <gsun@redhat.com>
blockcopy: Add regression case for bug 1134294

The bug is depend on qemu bug which not fixed yet, it's 100% reproducible.
Add the test case in possitive case, so the case will fail for now, the
error info contains the bug info.

Also with --pivot --async option, blockcopy will fail with the bug, so
check the error msg and log the bug info.

Signed-off-by: Wayne Sun <gsun@redhat.com>
blockcopy: Raise error when blockcopy timeout

As blockcopy will got hang due to bug 1134294, so set the timeout
for virsh command, also check the error in libvirtd log after command
timeout.

Signed-off-by: Wayne Sun <gsun@redhat.com>
Merge pull request #359 from waynesun09/blockcopy_update

blockcopy: Add nfs disk target testing case