Already-expired guards nobody noticed

The current version is 2.17.58, so every < 2.16.53 and < 2.17.53 guard has already fired, silently:

• lustre/osd-ldiskfs/osd_lproc.c:39 and lustre/osd-zfs/osd_lproc.c:26 (< 2.17.53) removed the symlink_brw_stats module parameter. A site with options osd_ldiskfs symlink_brw_stats=1 in modprobe.d now gets, on a current build: osd_ldiskfs: unknown parameter 'symlink_brw_stats' ignored. The module still loads; the setting is silently dropped and brw_stats never appears where the admin expected it. Nothing failed loudly.
• lustre/ptlrpc/sec_lproc.c:173,259 + lustre/utils/l_getsepol.c:498 (< 2.16.53) dropped the old SELinux-policy downcall magic on both sides at once. Fine as long as l_getsepol and the kernel modules are upgraded together; it silently breaks a mixed userspace/kernel install.
• lustre/utils/obd.c:4743 (> 2.17.52) and :5427 (> 2.17.53) started printing deprecation notices to stdout, which any test parsing lctl nodemap_* output will see.