Update index.lua

Prevent an error when the voicemail_uuid is empty when the voicemail box is disabled.

resources/install/scripts/app/voicemail/index.lua

@@ -320,6 +320,9 @@
 --leave a message
 	if (voicemail_action == "save") then
 
+		--valid voicemail
+			if (voicemail_uuid ~= nil) then
+
 				--check the voicemail quota
 					if (vm_disk_quota) then
 						--get voicemail message seconds
@@ -341,9 +344,6 @@
 							end
 					end
 
-		--valid voicemail
-			if (voicemail_uuid ~= nil) then
-
 				--play the greeting
 					timeouts = 0;
 					play_greeting();