GssTsigContextTest.signBadVerify fails on FreeBSD

Recent regression on FreeBSD, possibly after merging issue 3552.

[ RUN      ] GssTsigContextTest.signBadVerify
gss_tsig_context_unittests.cc:645: Failure
Expected equality of these values:
  TSIGError::BAD_SIG()
    Which is: BADSIG
  error
    Which is: NOERROR
gss_tsig_context_unittests.cc:646: Failure
Expected equality of these values:
  TSIGError::BAD_SIG()
    Which is: BADSIG
  ctx->getError()
    Which is: NOERROR
gss_tsig_context_unittests.cc:648: Failure
Expected equality of these values:
  (((OM_uint32) 6ul) << 16)
    Which is: 393216
  srv_key->getSecCtx().getLastError()
    Which is: 0
[  FAILED  ] GssTsigContextTest.signBadVerify (1 ms)