Bugfix: if no bestblock record is present, do a -rescan
Bugfix: if no bestblock record is present, do a -rescan

It is possible to have a wallet.dat file without any bestblock
record at all (if created offline, for example), which - when
loaded into a client with a up-to-date chain - does no rescan and
shows no transactions.

Also make sure to write the current best block after a rescan, so
it isn't necessary twice.

Crowndev/crowncoin,Infernoman/crowncoin,domob1812/crowncoin,syscoin/syscoin,domob1812/crowncoin,Crowndev/crowncoin,dobbscoin/dobbscoin-source,dobbscoin/dobbscoin-source,domob1812/crowncoin,syscoin/syscoin,syscoin/syscoin,Earlz/dobbscoin-source,Infernoman/crowncoin,Earlz/dobbscoin-source,Crowndev/crowncoin,Earlz/dobbscoin-source,dobbscoin/dobbscoin-source,syscoin/syscoin,domob1812/crowncoin,domob1812/crowncoin,dobbscoin/dobbscoin-source,syscoin/syscoin,Crowndev/crowncoin,domob1812/crowncoin,Earlz/dobbscoin-source,dobbscoin/dobbscoin-source,syscoin/syscoin,Crowndev/crowncoin,Crowndev/crowncoin,syscoin/syscoin,syscoin/syscoin,dobbscoin/dobbscoin-source,Infernoman/crowncoin,Infernoman/crowncoin,Earlz/dobbscoin-source,Earlz/dobbscoin-source,Infernoman/crowncoin,Infernoman/crowncoin