Git cookbook profiler needs better error message when it fails on windows symlinks

[danielsdeleo]

Many git commands don't work correctly if the git repo is in a windows symlink. In ChefDK, this can manifest as an error like:

Error: Failed to generate Policyfile.lock 
Reason: (Mixlib::ShellOut::ShellCommandFailed) Expected process to exit with [0], but received '128' 
---- Begin output of git symbolic-ref -q HEAD ---- 
STDOUT: 
STDERR: fatal: Invalid symlink 'C:/vagrant': Function not implemented 
---- End output of git symbolic-ref -q HEAD ---- 

Based on mailing list discussions, it seems like this can't/won't be fixed by git/msys-git folks. There is a FAQ entry about it here: https://github.com/msysgit/msysgit/wiki/Why-am-I-getting-fatal-Invalid-symlink-....-Function-not-supported.-error-when-initcloneing

However, the newer distribution of git for windows makes it seem like symlinks might work a little better on newer versions of Git: https://github.com/git-for-windows/git/wiki/Symbolic-Links

In either case, since users may not know about the cookbook profiler feature, they'll probably find it unexpected that ChefDK is running git commands on their path: cookbooks, so this error will be a crappy experience. At the very least, it would be good to raise a custom error type with more in-depth information than just the raw git error.