arpack-ng conflicts with homebrew's one

[samueljohn]

brew link julia
Linking /usr/local/Cellar/julia/HEAD... 
Error: Could not symlink file: /usr/local/Cellar/julia/HEAD/lib/libarpack.dylib
Target /usr/local/lib/libarpack.dylib already exists. You may need to delete it.
To force the link and delete this file, do:
  brew link -f formula_name

To list all files that would be deleted:
  brew link -n formula_name

because

brew info arpack-ng
arpack-ng: stable 3.1.0
http://forge.scilab.org/index.php/p/arpack-ng
Depends on: open-mpi
/usr/local/Cellar/arpack-ng/3.1.0 (10 files, 2.5M) *
https://github.com/staticfloat/homebrew-julia/commits/master/arpack-ng.rb

[staticfloat]

Closing this as a duplicate of #3