bashrc: minor fixes for error handling etc.
bashrc: minor fixes for error handling etc.

 - return non-zero on errors

 - print error messages to stderr

 - never reset PATH if for some reason PERLBREW_ROOT is empty

dagolden/App-perlbrew,calid/App-perlbrew,josl/App-perlbrew,calid/App-perlbrew,josl/App-perlbrew,rafl/App-perlbrew,Asuza/App-perlbrew,ptolemarch/App-perlbrew,ptolemarch/App-perlbrew,rafl/App-perlbrew,ptolemarch/App-perlbrew,Asuza/App-perlbrew,Asuza/App-perlbrew,josl/App-perlbrew,dagolden/App-perlbrew,rafl/App-perlbrew