switch_root: print errno on failure

diff --git a/util-linux/switch_root.c b/util-linux/switch_root.c
index 21cc992..08aa725 100644
--- a/util-linux/switch_root.c
+++ b/util-linux/switch_root.c
@@ -97,7 +97,7 @@
 	// Overmount / with newdir and chroot into it.  The chdir is needed to
 	// recalculate "." and ".." links.
 	if (mount(".", "/", NULL, MS_MOVE, NULL))
-		bb_error_msg_and_die("error moving root");
+		bb_perror_msg_and_die("error moving root");
 	xchroot(".");
 	xchdir("/");