Fail GetTransaction when the block from txindex is not in mapBlockIndex (#3606)
Fail GetTransaction when the block from txindex is not in mapBlockIndex (#3606)

This indicates a previous crash where the TX made it into the txindex but
the block was not flushed to disk. When dashd is restarted then, there is
a short time where GetTransaction would return a non-existant block, while
callers very often assume that the returned block hash is known.
thelazier/dash,dashpay/dash,UdjinM6/dash,dashpay/dash,UdjinM6/dash,dashpay/dash,UdjinM6/dash,UdjinM6/dash,dashpay/dash,thelazier/dash,thelazier/dash,thelazier/dash,UdjinM6/dash,thelazier/dash,dashpay/dash