If things get installed by something other than the system package
manager they often end up in /usr/local/bin and they often shadow things
that the system package manager may have installed. By putting this at
the end of the path we don't get the benefit of that shadowing and
instead get whatever the system package manager installed.
This is particularly unhelpful when attempting to use an npm updated by
npm itself which ends up in the local dir.
Change-Id: Ifb58c98162f0064a2ae70868921eea507306ad7e
411f392c14