Consider SIGHASH_ALL while reading votes from block

[Patricia92]

In either case, the change is accepted if a sufficiently privileged user signed any input with the signature type SIGHASH_ALL, or if they signed the input with the same index as that output with SIGHASH_SINGLE. https://www.multichain.com/developers/permissions-management/

We only consider SIGHASH_SINGLE in function getblock() in sync.py.