Minor fixes coming from comparison between laterst master vs develop.
Changes required by linter.
Changes required for SMT code to compile.
Test db_remove_expired_governance_votes
extended to cover proxy setup/removal before HF25.
Added test (not yet enabled) for interaction between decline_voting_rights_operation
and governance vote expiration (will be enabled when we fix a bug that lets nonvoting account to vote on proposals).
Corrections in indents, dangling comment removed.
[Note]: there are some big problems spotted in the comparison - these will be fixed in separate MRs.