doc: fix broken link in SHEC erasure code plugin

Fixes: http://tracker.ceph.com/issues/16996

Signed-off-by: Albert Tu <albert.t@inwinstack.com>

doc/rados/operations/erasure-code-shec.rst

@@ -3,7 +3,7 @@ SHEC erasure code plugin
 ========================
 
 The *shec* plugin encapsulates the `multiple SHEC
-<https://wiki.ceph.com/Planning/Blueprints/Hammer/Shingled_Erasure_Code_(SHEC)>`_
+<http://tracker.ceph.com/projects/ceph/wiki/Shingled_Erasure_Code_(SHEC)>`_
 library. It allows ceph to recover data more efficiently than Reed Solomon codes.
 
 Create an SHEC profile