revert change to ignore_skip_worktree in git checkout and `git re…

…store` (#674)

This reverts #658 and essentially reopens microsoft/VFSForGit#1812.
Resolves #673.

The issue is that by overriding the `ignore_skip_wortree` value
(normally set by `--ignore-skip-worktree`) we then force Git to hydrate
the entire working directory in a `git restore .`. This leads to some
interesting trade-offs:

1. Users on v2.45.2.vfs.0.2 (where `git restore .` overhydrates), they
can use `git reset --hard` as a better representation of this behavior.
2. Users on any Git version can use `git restore --ignore-skip-worktree
-- <pathspec>` when using a smaller-scale pathspec that corresponds to
files they care about and probably have hydrated.

I will include these workarounds in the VFS for Git issue.

To get to a real solution here, we would somehow need to turn the
`ignore_skip_worktree` bit into two bits:

a. A bit to say "update index entries that have `SKIP_WORKTREE` set".
b. A bit to say "update the working directory even if `SKIP_WORKTREE` is
set".

And perhaps this "working directory" version is what was intended when
adding the `--ignore-skip-worktree` option, but it's more involved and
has upstream implications to make changes here.

builtin/checkout.c

@@ -1,6 +1,5 @@
 #define USE_THE_INDEX_VARIABLE
 #include "builtin.h"
-#include "gvfs.h"
 #include "advice.h"
 #include "branch.h"
 #include "cache-tree.h"
@@ -1759,7 +1758,6 @@ static int checkout_main(int argc, const char **argv, const char *prefix,
 	}
 
 	opts->track = BRANCH_TRACK_UNSPECIFIED;
-	opts->ignore_skipworktree = gvfs_config_is_set(GVFS_USE_VIRTUAL_FILESYSTEM);
 
 	if (!opts->accept_pathspec && !opts->accept_ref)
 		BUG("make up your mind, you need to take _something_");