Allow spaces in quoted SSH command arguments

The check_ssh_injection() method was rejecting arguments with spaces
even when they were quoted, this was causing problems with some volume
driver commands such as commands for a storage pool with spaces in the
name.

Note that this backport also fixes a typo that has been fixed separately
in master with commit eb0f2e4dd538a79184efbb23d7e404147dfe877b .

Closes-Bug: #1244415
Change-Id: Ie4b809e1b39fdb752cf634e6d3c0a3924d8ac52b
(cherry picked from commit 2737c76cb2fb436f117a4f635aebca7a01691d88)
Don't zero out thin provisioned LV's on delete

Thin provisioned LV's don't need secure delete to protect
from data leakage.  Also, zeroing these out kinda defeats
the purpose of using thing provisioning.

This patch add a check for the lvm type and if it's thin simply
returns from the lvm.clear_volume() method.

Change-Id: Ie6764209018152565295291efc6fbba553698ae6
Closes-Bug: #1240299
(cherry picked from commit de4392314f9b0def8fab65679ec5668aec98fbee)
Merge "Allow spaces in quoted SSH command arguments" into stable/havana