Assert that deps can be installed under node 0.8's npm (#2236)

Author: dasilvacontin

scripts/ensure-compatible-npm.sh

@@ -5,6 +5,8 @@ set -o errexit
 
 npm install semver
 if node -e "process.exit(require('semver').lt(process.argv[1], '1.3.7') ? 0 : 1)" $(npm -v); then
+  # make sure dependencies install with provided npm version
+  npm install --production
   npm install -g npm@2
   npm install -g npm
 fi