Refactor reset_to_discover procedure

Added reset_to_discover method which should be used
when node resetted to discovery state.
- Reconfigure volumes
- Move roles to pendings roles
- Remove assigned ip address
- Set pending addition

Change-Id: I07f1d12f904e8faa76e35f00a49a978a6643eb20
Closes-Bug: 1389572
Related-Bug: 1273006
Merge "Refactor reset_to_discover procedure"