Add sleep(1) to /rescue.  This adds 664 bytes to the binary on amd64 but
it's pretty useful for shell scripts.

MFC after:	1 month
Sponsored by:	iXsystems, Inc.


git-svn-id: svn+ssh://svn.freebsd.org/base/head@275435 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f