Such directory entries need special handling to make our directory traversal code work on filesystems that do not support the d_type optimization. I found this problem because references stored in the refs/ directory were not shown by 'got log' and 'tog log' when a repository is mounted over NFS. helpful feedback + ok millert@

Problem reported by semarie, who also provided initial regression test code. ok semarie

This makes it easier to tell in which code paths we are expecting to handle a potential 'ie' NULL pointer and avoids a pointless search of the file index.

fix rash pointer change in last edit

correct a lot of incorrect error handling adjust copyrights

this is for got push and got fetch, primarily ok stsp

ok tracey stsp

approach suggested by ori@ and matches how git9 behaves ok semarie@ (who can now work with Rust-related Git repos containing submodules)

ok semarie