Do not use sctx to access the ib_tx_t *.
Merge pull request #5 in RNS/ironbee from ~SBASKINGER/ironbee:0.11.x to 0.11.x

* commit '2ad5d5d4d5275c8f52bc198968b72808e164aa29':
  Do not use sctx to access the ib_tx_t *.