remove old rewrite rules for AlwaysOn from web.config (#6968)

Author: safihamid

src/WebJobs.Script.WebHost/web.config

@@ -19,17 +19,6 @@
         <requestLimits maxQueryString="4096" maxUrl="8192" maxAllowedContentLength="104857600"/>
       </requestFiltering>
     </security>
-    <rewrite>
-      <rules>
-        <rule name="AlwaysOn Ping Rewrite" stopProcessing="true">
-          <match url="^$" />
-          <conditions>
-            <add input="{HTTP_USER_AGENT}" pattern="^AlwaysOn$" />
-          </conditions>
-          <action type="Rewrite" url="/admin/host/ping" />
-        </rule>
-      </rules>
-    </rewrite>
   </system.webServer>
   <runtime>
     <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">