support platforms which does not have shasum command
support platforms which does not have shasum command

use sha1sum command if there is no shasum command

JasonChrYoung/nvm,edwmurph/nvm,diegofcb10/nvm,woss/nvm,wahyutaufik/nvm,parasaro92/nvm,mmorejon/nvm,williamboman/nvm,devedbox/nvm,bbuck/nvm,hanhailong/nvm,joneit/nvm,thomasf/nvm,dfackler/nvm,WY08271/nvm,JasonChrYoung/nvm,WY08271/nvm,CristianCantoro/nvm,cirosantilli/nvm,bevacqua/nvm,SampleLiao/nvm,jhliberty/nvm,vinaykaradia/clone-nvm,Theodeus/nvm,Richardphp/nvm,woss/nvm,hkdobrev/nvm,tianzhihen/nvm,appleboy/nvm,domenicosolazzo/nvm,NicCollins/nvm,dfackler/nvm,Theodeus/nvm,owen-it/nvm,tianzhihen/nvm,mmorejon/nvm,youleiy/nvm,PeterDaveHelloKitchen/nvm,egilkh/nvm,vinaykaradia/clone-nvm,bevacqua/nvm,michael-ni/nvm,pmq20/nvm,kumaria/nvm,christophercaburog/nvm,reybango/nvm,greyhwndz/nvm,reybango/nvm,icyflame/nvm,gtdeng/nvm,IonicaBizauKitchen/nvm,lukechilds/nvm,misterdjules/nvm,egilkh/nvm,kumaria/nvm,jaawerth/nvm,tlevine/nvm,sjfkai/nvm,icyflame/nvm,pmq20/nvm,LeeLovCY/nvm,diegofcb10/nvm,cnpm/nvm,IonicaBizauKitchen/nvm,Kuzirashi/nvm,SampleLiao/nvm,Salahudeen/nvm,ljharb/nvm,evocateur/nvm,williamboman/nvm,nontage24/nvm,fnogatz/swivm,JanChw/nvm,psychoss/nvm,cjac/nvm,thomasf/nvm,jaawerth/nvm,slariviere/nvm,elrasguno/nvm,greyhwndz/nvm,chinazhaghai/nvm,Salahudeen/nvm,scq000/nvm,nontage24/nvm,wskplho/nvm,jbergstroem/nvm,Richardphp/nvm,edwmurph/nvm,owen-it/nvm,PeterDaveHello/nvm,devedbox/nvm,creationix/nvm,scq000/nvm,michael-ni/nvm,xtuple/nvm,mirydz/nvm,hanhailong/nvm,lukechilds/nvm,evocateur/nvm,misterdjules/nvm,Ingelheim/nvm,DigitallySeamless/nvm,Ingelheim/nvm,modulexcite/nvm,joneit/nvm,PeterDaveHelloKitchen/nvm,PeterDaveHello/nvm,bbuck/nvm,jbergstroem/nvm,jhliberty/nvm,elrasguno/nvm,kmctown/nvm,wahyutaufik/nvm,Kuzirashi/nvm,youleiy/nvm,christophercaburog/nvm,kmctown/nvm,slariviere/nvm,JanChw/nvm,parasaro92/nvm,hkdobrev/nvm,wskplho/nvm,modulexcite/nvm,gtdeng/nvm,ljharb/nvm,tlevine/nvm,chinazhaghai/nvm,mirydz/nvm,DigitallySeamless/nvm,creationix/nvm,CristianCantoro/nvm,domenicosolazzo/nvm,cnpm/nvm,cirosantilli/nvm,cjac/nvm,psychoss/nvm,LeeLovCY/nvm