Adding rm/del instruction for agents.

pkg/templates/usage.templ

@@ -15,10 +15,12 @@ templ Usage(secure string, host string, username string) {
            `}curl http{secure}://{host}/static/agent > agent{`
            chmod 755 agent
            `}./agent --id ID ws{secure}://{host}{`
+           rm -f agent
 
            # windows
            `}curl http{secure}://{host}/static/agent.exe > agent.exe{`
            `}agent --id ID ws{secure}://{host}{`
+           del agent.exe
           `}</pre>
                       <p>
                           Above, ID is a unique id for the job, the so-called rendez-cous ID. This should not conflict with IDs