MEDIUM: server: remove experimental-mode for dynamic servers

Dynamic servers feature is now judged to be stable enough. Remove the
experimental-mode requirement for "add/del server" commands. This should
facilitate dynamic servers adoption.
diff --git a/reg-tests/server/cli_add_ssl_server.vtc b/reg-tests/server/cli_add_ssl_server.vtc
index 843958d..95caf3f 100644
--- a/reg-tests/server/cli_add_ssl_server.vtc
+++ b/reg-tests/server/cli_add_ssl_server.vtc
@@ -70,7 +70,7 @@
 
 haproxy h1 -cli {
 	# non existent backend
-	send "experimental-mode on; add server li-ssl/s1 ${h1_feSslTerm_addr}:${h1_feSslTerm_port} ssl ca-file common.pem verify none"
+	send "add server li-ssl/s1 ${h1_feSslTerm_addr}:${h1_feSslTerm_port} ssl ca-file common.pem verify none"
 	expect ~ "New server registered."
 
 	send "enable server li-ssl/s1"