ciao-down: update to golang 1.7.4
ciao-down: update to golang 1.7.4

Golang 1.7.4 is available and ciao-down should use it instead of 1.7.3

Signed-off-by: Tim Pepper <8dbd764830e941d092a1cb7fa16423169acc0b04@linux.intel.com>

rbradford/ciao,01org/ciao,obedmr/ciao,mrkz/ciao,tpepper/ciao,ciao-project/ciao,matthewrsj/ciao,markdryan/ciao,ciao-project/ciao,rbradford/ciao,obedmr/ciao,01org/ciao,mrkz/ciao,mrkz/ciao,mcastelino/ciao,matthewrsj/ciao,erick0z/ciao,kaccardi/ciao,tpepper/ciao,mcastelino/ciao,mcastelino/ciao,erick0z/ciao,wcwxyz/ciao,markdryan/ciao,matthewrsj/ciao,obedmr/ciao,erick0z/ciao,wcwxyz/ciao,wcwxyz/ciao,kaccardi/ciao,tpepper/ciao