path.c: migrate global git_path_* to take a repository argument

Migrate all git_path_* functions that are defined in path.c to take a
repository argument. Unlike other patches in this series, do not use the
 #define trick, as we rewrite the whole function, which is rather small.

This doesn't migrate all the functions, as other builtins have their own
local path functions defined using GIT_PATH_FUNC. So keep that macro
around to serve the other locations.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/builtin/fetch.c b/builtin/fetch.c
index 5514067..41d74c7 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -767,7 +767,7 @@ static int store_updated_refs(const char *raw_url, const char *remote_name,
 	const char *what, *kind;
 	struct ref *rm;
 	char *url;
-	const char *filename = dry_run ? "/dev/null" : git_path_fetch_head();
+	const char *filename = dry_run ? "/dev/null" : git_path_fetch_head(the_repository);
 	int want_status;
 	int summary_width = transport_summary_width(ref_map);
 
@@ -1019,7 +1019,7 @@ static void check_not_current_branch(struct ref *ref_map)
 
 static int truncate_fetch_head(void)
 {
-	const char *filename = git_path_fetch_head();
+	const char *filename = git_path_fetch_head(the_repository);
 	FILE *fp = fopen_for_writing(filename);
 
 	if (!fp)