message: scripts/eosio_build_darwin.sh: fix typo
diff: if brew list | grep "boost"
  then
  printf "\\tUnlinking Boost Version %s.\\n" "${BVERSION}"
  - printff "\\tunlinking boost %s\\n" "${BVERSION}"
  + printf "\\tunlinking boost %s\\n" "${BVERSION}"
  if ! "${BREW}" unlink boost
  then
  printf "\\tUnable to remove boost libraries at this time. 0\\n"
  