projectile-follow-symlinks in projectile-file-truename

I ran into this issue using clearcase -- I was trying to create a directory with soft links to the dynamically mounted vobs, and once I was in the vob, projectile couldn't resolve the project because file-truename follows symlinks :(

I tried just disabling `file-symlink-p` in .dir-locals, but then I needed symlinks resolved for `vc-mode`.

So I have been using this PR for a day or so, and I have seen no problems using it with clearcase or another project where symlinks are being followed.

Let me know if there is anything else I can do for this!