Split test_rebuild() into two tests

The method tests rebuilds with and without passwords, but the tests are
independent and should be in two seperate tests.

Also, remove duplication of the rebuild with password test from
test_rebuild_preserve_ephemeral

Change-Id: I40d0376fabf319dbe703d593de8fb4cdcf0aeab1
Remove py3kcompat

It's not used by novaclient anymore and isn't used by any other
openstack common code either.

Change-Id: I96ebf030d0a96436a8a75c6937c354003ee32c58
Closes-bug: 1280033
Print adminPass when rebuilding from shell

The 'nova rebuild' command did not print the adminPass returned by the
server. This is because it discards the instance information returned
by the rebuild action and fetchs the information again. This would lose
the adminPass and it would not be printed for the user.

This patch reuses the instance information returned by the rebuild action
which ensures that the adminPass is printed by the shell.

Change-Id: I144bfa298bef529c78ca04042cd37a763537f09e
Closes-bug: 1302696
Merge "Remove py3kcompat"
Merge "Print adminPass when rebuilding from shell"