Remove libselinux-python hack

We are now running the zuul-worker element, so this logic can be
removed.

Change-Id: I7dd224a50817a638e2e65ba27aa8807a99d90702
Signed-off-by: Paul Belanger <pabelanger@redhat.com>
diff --git a/zuul/launcher/ansiblelaunchserver.py b/zuul/launcher/ansiblelaunchserver.py
index 45704c1..fe29429 100644
--- a/zuul/launcher/ansiblelaunchserver.py
+++ b/zuul/launcher/ansiblelaunchserver.py
@@ -993,12 +993,6 @@
                                   state='directory'))
             main_block.append(task)
 
-            # TODO: remove once zuul-worker DIB element has landed
-            main_block.append(dict(shell="[ -f /usr/bin/yum ] && "
-                                   "sudo /usr/bin/yum install "
-                                   "libselinux-python || "
-                                   "/bin/true"))
-
             for builder in jjb_job.get('builders', []):
                 if 'shell' in builder:
                     main_block.extend(