Fixes and refactorings related to using mnsync in tests#3136

Merged

UdjinM6 merged 2 commits intodashpay:developfrom

UdjinM6:dropwaitsync

Oct 9, 2019

Commits on Oct 7, 2019

Drop `get_mnsync_status`, `wait_to_sync` and `sync_masternodes` and introduce `force_finish_mnsync` for MNs only
UdjinM6
committed
Use `force_finish_mnsync` from util.py in dip3-deterministicmns.py and drop local unused functions
UdjinM6
committed