Please support git_repository_set_index

[joshtriplett]

libgit2 provides a function git_repository_set_index to set the index of a repository, useful for doing index-based operations without disrupting the current state in .git/index. Please consider providing a git::Repository::set_index function to access that.

[alexcrichton]

Sure! Bindings basically aren't ever left out intentionally, just haven't gotten around to writing it yet.

[joshtriplett]

I'm not entirely sure if this is the correct type signature. The underlying function definitely needs to mutate the index (setting the owner, specifically). But I see many functions in git2-rs that seem to hide mutation behind a plain & rather than a &mut, including all the Repository functions.

[joshtriplett]

The Travis failure here looks like some spurious issue with systest, unrelated to this commit. Looking at the log, the testsuite looks like it passed.

[alexcrichton]

Thanks!