[Dockerfile] Add missing quotes for variables
[Dockerfile] Add missing quotes for variables

evocateur/nvm,edwmurph/nvm,ljharb/nvm,ljharb/nvm,creationix/nvm,edwmurph/nvm,PeterDaveHello/nvm,evocateur/nvm,PeterDaveHello/nvm,PeterDaveHelloKitchen/nvm,creationix/nvm,PeterDaveHelloKitchen/nvm