[monitoring-plugins] Fix: Use macro for perl binary

[Bernd Arnold]

 Module: monitoring-plugins
 Branch: master
 Commit: 9ee884b3de6c95f871a714dfc67cfb9b5e11724f
 Author: Bernd Arnold <wopfel at gmail.com>
   Date: Wed Jun 13 15:57:16 2018 +0200
    URL: https://www.monitoring-plugins.org/repositories/monitoring-plugins/commit/?id=9ee884b

Fix: Use macro for perl binary

I've messed that up in the previous commit 554b702f9d65fdfe640f20633543e00cd79d64ac.

---

 plugins-scripts/check_uptime.pl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/plugins-scripts/check_uptime.pl b/plugins-scripts/check_uptime.pl
index 20234c8..8817030 100755
--- a/plugins-scripts/check_uptime.pl
+++ b/plugins-scripts/check_uptime.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl -w
+#!@PERL@ -w
 
 # check_uptime - check uptime to see how long the system is running.
 #