tests: make bootstrap work on the target not localhost

Signed-off-by: Gregory Meno <gregory.meno@inktank.com>
tests: fix min_size when default_min_size is 0

Signed-off-by: Gregory Meno <gregory.meno@inktank.com>
tests: move quoting to _run_command

Signed-off-by: Gregory Meno <gregory.meno@inktank.com>
tests: add note to improve _run_command later

Signed-off-by: Gregory Meno <gregory.meno@inktank.com>
Merge pull request #187 from ceph/wip-8968

Wip 8968