remove revision that does not exist

error fro mjenkins:

* Error installing a repository (after 0:00:00.102918 seconds)! Name: purge_dups,owner: iuc,
revision: cf13a1e03e5b, error: {"err_msg": "No information is available for the requested
repository revision.\nOne or more of the following parameter values is likely invalid:
\ntool_shed_url: https://toolshed.g2.bx.psu.edu/\nname: purge_dups\nowner: iuc\nchangeset_revision: cf13a1e03e5b\n", "err_code": 400008}

usegalaxy.org/assembly.yml.lock

@@ -228,7 +228,6 @@ tools:
   - 29151e779524
   - 76d4cbefff85
   - a315c25dc813
-  - cf13a1e03e5b
   - e9bd16ba5ebd
   tool_panel_section_id: assembly
   tool_panel_section_label: Assembly