Merge branch 'tr/protect-low-3-fds'

When "git" is spawned in such a way that any of the low 3 file
descriptors is closed, our first open() may yield file descriptor 2,
and writing error message to it would screw things up in a big way.

* tr/protect-low-3-fds:
  git: ensure 0/1/2 are open in main()
  daemon/shell: refactor redirection of 0/1/2 from /dev/null

git.c

@@ -525,6 +525,13 @@ int main(int argc, char **av)
 	if (!cmd)
 		cmd = "git-help";
 
+	/*
+	 * Always open file descriptors 0/1/2 to avoid clobbering files
+	 * in die().  It also avoids messing up when the pipes are dup'ed
+	 * onto stdin/stdout/stderr in the child processes we spawn.
+	 */
+	sanitize_stdfds();
+
 	git_setup_gettext();
 
 	/*