Test for remote directory creation before shutting down instance

This patch moves the creation of the directory on the migration target
earlier in the code path so we can catch failures like missing or incorrect
keypairs on the source and destination node.

This fixes part of bug #1061024 but not all of it yet.

Change-Id: I097cf007cdd8de0c9c3a9390cbc6dc202eddb2b5
Merge "Test for remote directory creation before shutting down instance"