Remove XPI and JAR MIME types from httpd config

We added MIME types for JAR and XPI files, which were needed for
correct handling of the Firefox auto-configuration plugin.  The
plugin was removed some time ago, so remove the media type
definitions.

Part of: https://pagure.io/freeipa/issue/7226

Reviewed-By: Rob Crittenden <rcritten@redhat.com>

install/conf/ipa.conf

@@ -27,10 +27,6 @@ KeepAliveTimeout 30
 
 # ipa-rewrite.conf is loaded separately
 
-# This is required so the auto-configuration works with Firefox 2+
-AddType application/java-archive        jar
-AddType application/x-xpinstall         xpi
-
 # Proper header for .tff fonts
 AddType application/x-font-ttf          ttf