Fix: if not exist Date-header

conf/lua/rspamd.lua

@@ -45,8 +45,8 @@ rspamd_config.DATE_IN_FUTURE = function(task)
 	if rspamd_config:get_api_version() >= 5 then
 		local dm = task:get_date{format = 'message'}
 		local dt = task:get_date{format = 'connect'}
-		-- An hour
-		if dm - dt > 7200 then
+		-- An 2 hour
+		if dm > 0 and dm - dt > 7200 then
 			return true
 		end
 	end
@@ -58,7 +58,7 @@ rspamd_config.DATE_IN_PAST = function(task)
     local dm = task:get_date{format = 'message', gmt = true}
     local dt = task:get_date{format = 'connect', gmt = true}
 		-- A day
-		if dt - dm > 86400 then
+		if dm > 0 and dt - dm > 86400 then
 			return true
 		end
 	end