LU-15732 test: don't set RSYNC_SSH=rsh

LU-15732 test: don't set RSYNC_SSH=rsh

Let rsync use ssh (the default) in test-framework.sh.

Signed-off-by: John L. Hammond <jhammond@whamcloud.com>
Change-Id: I31fafc72b476070f0a16c1578bc014cc68e21424
Reviewed-on: https://review.whamcloud.com/47032
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: James Casper <jcasper@ddn.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>