have _npm_install do prune, install, AND update
have _npm_install do prune, install, AND update

update alone doesn't seem to install js-xapth on npm 1.x

qedsoftware/commcare-hq,dimagi/commcare-hq,dimagi/commcare-hq,qedsoftware/commcare-hq,dimagi/commcare-hq,dimagi/commcare-hq,qedsoftware/commcare-hq,qedsoftware/commcare-hq,dimagi/commcare-hq,qedsoftware/commcare-hq