Fix a genuine off-by-one error that caused join to dump core when trying to use field numbers tha weren't present in the input data.
Fix a genuine off-by-one error that caused join to dump core when
trying to use field numbers tha weren't present in the input data.

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase