Homebrew complains about up-config

[mattwiebe]

I have node/npm installed via homebrew on a Mac as well as up(1).

When I run brew doctor to ensure that things are silky smooth, it complains:

Warning: "config" scripts exist outside your system or Homebrew directories.
`./configure` scripts often look for *-config scripts to determine if
software packages are installed, and what additional flags to use when
compiling and linking.

Having additional scripts in your path can confuse software installed via
Homebrew if the config script overrides a system or Homebrew provided
script of the same name. We found the following "config" scripts:

    /usr/local/share/npm/bin/up-config

Be nice to use a different filename if possible.