Silence the warning
Silence the warning

Fish warns if a non-existant directory is added to $PATH.
Which can happens for some installs of perlbrew.

Fixes #446

Asuza/App-perlbrew,josl/App-perlbrew,Asuza/App-perlbrew,ptolemarch/App-perlbrew,josl/App-perlbrew,ptolemarch/App-perlbrew,ptolemarch/App-perlbrew,Asuza/App-perlbrew,josl/App-perlbrew