getblocktemplate errors out when a non-fully spent transaction is included

[jolan]

I mentioned this on IRC and it was agreed that this should be caught.

08:33:54 2015-04-21 [ERR] RPCS: Failed to create new block template: tried to overwrite transaction 62aae0b3827ffaaad088bdb1dbae505cab43d8a9c5939c8b8bad8a88c01b13a6 at block height 353091 that is not fully spent

This causes bfgminer to fall back to getwork:

[2015-04-21 08:33:54] Pool 0 failed getblocktemplate request; falling back to getwork protocol
[2015-04-21 08:33:54] Pool 0 http://localhost:8334