shared repository - add a few missing calls to adjust_shared_perm().

There were a few calls to adjust_shared_perm() that were
missing:

 - init-db creates refs, refs/heads, and refs/tags before
   reading from templates that could specify sharedrepository in
   the config file;

 - updating config file created it under user's umask without
   adjusting;

 - updating refs created it under user's umask without
   adjusting;

 - switching branches created .git/HEAD under user's umask
   without adjusting.

This moves adjust_shared_perm() from sha1_file.c to path.c,
since a few SIMPLE_PROGRAM need to call repository configuration
functions which in turn need to call adjust_shared_perm().
sha1_file.c needs to link with SHA1 computation library which
is usually not linked to SIMPLE_PROGRAM.

Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/builtin-init-db.c b/builtin-init-db.c
index 88b39a4..6a24e9b 100644
--- a/builtin-init-db.c
+++ b/builtin-init-db.c
@@ -199,6 +199,21 @@
 	git_config(git_default_config);
 
 	/*
+	 * We would have created the above under user's umask -- under
+	 * shared-repository settings, we would need to fix them up.
+	 */
+	if (shared_repository) {
+		path[len] = 0;
+		adjust_shared_perm(path);
+		strcpy(path + len, "refs");
+		adjust_shared_perm(path);
+		strcpy(path + len, "refs/heads");
+		adjust_shared_perm(path);
+		strcpy(path + len, "refs/tags");
+		adjust_shared_perm(path);
+	}
+
+	/*
 	 * Create the default symlink from ".git/HEAD" to the "master"
 	 * branch, if it does not exist yet.
 	 */