do not hard-down the agent after banning

Signed-off-by: amoore877 <andrew.s.moore@uber.com>

test/integration/suites/evict-agent/06-agent-failed-to-start

@@ -1,8 +1,5 @@
 #!/bin/bash
 
-log-debug "restarting agent..."
-log-debug "bringing agent down..."
-docker-down spire-agent
 log-debug "starting agent again..."
 docker-up spire-agent