change genesis gasUsed to 0 in dataTx tests

[winsvega]

actually according to the YP scpecs we could remove genesis from tests.
https://ethereum.github.io/yellowpaper/paper.pdf

Appendix I. Genesis Block
The genesis block is 15 items, and is specified thus:
(300) 0256,
KEC
RLP
()��, 0160, stateRoot, 0, 0, 02048, 2
17
, 0, 0, 3141592, time, 0, 0256, KEC
(42)��,(),()�
Where 0256 refers to the parent hash, a 256-bit hash which is all zeroes; 0160 refers to the beneficiary address, a 160-bit
hash which is all zeroes; 02048 refers to the log bloom, 2048-bit of all zeros; 217 refers to the difficulty; the transaction trie
root, receipt trie root, gas used, block number and extradata are both 0, being equivalent to the empty byte array. The
sequences of both ommers and transactions are empty and represented by (). KEC
(42)�
refers to the Keccak hash of a
byte array of length one whose first and only byte is of value 42, used for the nonce. KEC
RLP
()�� value refers to the
hash of the ommer list in RLP, both empty lists.
The proof-of-concept series include a development premine, making the state root hash some value stateRoot. Also
time will be set to the initial timestamp of the genesis block. The latest documentation should be consulted for those
values.

this particular tests failing because of the gasUsed field in go client.