conpaas-director: use '!=' rather than 'is not' for string comparison


git-svn-id: svn://svn.forge.objectweb.org/svnroot/contrail/trunk/conpaas@5254 ef35cc4a-2640-4bbf-98bc-65920db7d8ae
conpaas-director: add test_upload_manifest_ok


git-svn-id: svn://svn.forge.objectweb.org/svnroot/contrail/trunk/conpaas@5255 ef35cc4a-2640-4bbf-98bc-65920db7d8ae