Catch IndexError when deserializing wallet transactions

[mecampbellsoup]

For now this PR just prevents the wallet-tool. wallet.json history command from throwing an exception due to "zero input transactions" (from what I can tell it seems like JM has created a transaction with zero unspent inputs but I'm not 100% sure).

[mecampbellsoup]

@AdamISZ @chris-belcher @adlai Here is an example of this PR in action, whereby the zero input/zero amount transaction is printed to the console:

" 622" "2017-XX-13 12:12" "unknown type" "0.00000000" "+0.00000000" "0.00000000" " 1" "#          " "  0" " #" " #"
" 623" "2017-XX-13 12:30" "unknown type" "0.00000000" "+0.00000000" "0.00000000" " 1" "#          " "  0" " #" " #"


{'script': ‘XXXX402203cb8f25c7e2694265c00f2c6570252a81e790322a9820ea8f4047a3dae4b01f302207f16bde1757dc5a68d520eb9aa473e21da01c4a05fb54619a76b068d107d3124012XXXXX63c2d07c008117f50Xd41a1d4881e2be9ab104XX966ff70eee3415ff898d1d', 'outpoint': {'index': 6, 'hash': '839274080baa001f2b74967b4e9eee985bXXXXXe0b4521ba14662f707729f2c0'}, 'sequence': XX94967295}


{'locktime': 2540440024, 'outs': [{'value': 175396634XX81069571L, 'script': '149b01d7744098c9dfe670cc8da3fe81e32abd1497a27XXXXX0000001716001470eb5212b558cfc10b31f0849ef88ecf17097ac1ffffffffb0a567112791b9ebceec17938d6930a1c8ef642e17624348b57ef59fd8096cXXXX0000001716001470eb5212b558cfc10b31f0849ef88ecf17097ac1ffffffffb0a567112791b9ebceec17938d6930a1c8ef64XX17624348b57ef59f'}], 'version': 2, 'ins': []}


" 624" "2017-XX-13 12:30" "unknown type" "0.00000000" "+0.00000000" "0.00000000" " 1" "#          " "  0" " #" " #"
" 625" "2017-XX-13 12:30" "unknown type" "0.00000000" "+0.00000000" "0.00000000" " 1" "#          " "  0" " #" " #"
" 626" "2017-XX-13 20:20" "unknown type" "0.00000000" "+0.00000000" "0.00000000" " 4" "#          " "  0" " #" " #"
" 627" "2017-XX-14 02:08" "unknown type" "0.00000000" "+0.00000000" "0.00000000" " 4" "#          " "  0" " #" " #"

Any idea what is going on here?