[pass] pass assumes tree parameters not available on all systems

[Soren Bjornstad]

Hello,

On my system I get the following error when trying to use ‘find’ in 
version 1.6.5 (and earlier versions):

     $ pass find whatever
     Search Terms: whatever
     tree: Invalid argument -`-’.

I tracked this down to line 336 of /usr/bin/pass, which uses the 
parameters --matchdirs and --ignore-case, which my version of tree 
doesn’t recognize. I solved the problem for myself by simply 
removing them from the code, but could pass be designed to fail more 
gracefully in this case?

For what it’s worth, I’m using Linux Mint 17.2 (based on the Ubuntu 
14.04 repositories), with a ‘tree’ 1.6.0, copyright by Steve Baker, 
Thomas Moore, Francesc Rocher, and Kyosuke Tokoro.

Feel free to ask for more information if it’s helpful. Thanks!

--Soren