Prior to this change, we had the condition

  optInterface == "" && optAutodetect || optBondingAuto

which by precedence rules is the same as

  (optInterface == "" && optAutodetect) || optBondingAuto

I think it makes more sense to write it as

  optInterface == "" && (optAutodetect || optBondingAuto)

I.e., never override a non-empty optInterface.

This changes behavior only when optInterface is provided (!= "") and
optBondingAuto is true (-B option). Which shouldn't happen, since from
my reading of the code, optInterface can be non-empty at this point
only if one of the -I, -m, or -b options are used, and those are
mutually exclusive with -B (as well as with -A, controlling the
optAutoDetect variable).