Run filestore with node6 (#108)

server-ce/runit/filestore-sharelatex/run

@@ -1,3 +1,3 @@
 #!/bin/bash
 export SHARELATEX_CONFIG=/etc/sharelatex/settings.coffee
-exec /sbin/setuser www-data /usr/bin/node /var/www/sharelatex/filestore/app.js >> /var/log/sharelatex/filestore.log 2>&1
+exec /sbin/setuser www-data /usr/bin/node6 /var/www/sharelatex/filestore/app.js >> /var/log/sharelatex/filestore.log 2>&1