build: Try not to cache node_modules on CI
build: Try not to cache node_modules on CI

To make sure dtrace-provider is recompiled.
See: https://travis-ci.org/cozy-labs/cozy-desktop/jobs/223061506

nono/cozy-desktop,cozy-labs/cozy-desktop,nono/cozy-desktop,cozy-labs/cozy-desktop,cozy-labs/cozy-desktop,cozy-labs/cozy-desktop,nono/cozy-desktop,nono/cozy-desktop