LVM: Activate source snap LV when cloning from volume

Similar to the change made in:
01a2199 LVM: Activate source LV before cloning from it

Previous change only fixed this issue for clone-from-snapshot.

This activates the source snapshot LV when cloning from volume
as well, fixing the problem where cloning fails due to inability
to open the source LV device.

Related-Bug: 1252423
Closes-Bug: 1260786

(cherry picked from commit 673057320929d33095c998d477c2537567ccf74b)

Change-Id: If48be8516fd71738cb83a91683c33d02f227b9d6
Sync latest process and str utils from oslo

This backport the necessary changes to fix both issues:
* Make execute method clean password in exception
* Make sure mask_password works properly

Backport in oslo-incubator: 4cf1a2a158f7c3c21799bf2e6ba0e7b5fbc25d62

Closes-Bug: 1343604
Closes-Bug: 1345233
SecurityImpact

Change-Id: I3b49b1d667f6ade9ae3f6765d735440a3e838917
Merge "LVM: Activate source snap LV when cloning from volume" into stable/havana