Update ZM_MIN_RTSP_PORT description

scripts/ZoneMinder/lib/ZoneMinder/ConfigData.pm.in

@@ -978,13 +978,12 @@ our @options = (
   {
     name        =>  'ZM_MIN_RTSP_PORT',
     default     =>  '',
-    description =>  'Start of port range to contact for RTSP streaming video.',
+    description =>  'Port used for RTSP streaming video.',
     help        =>  q`
-      The beginng of a port range that will be used to offer
+      The port that will be used to offer
       RTSP streaming of live captured video.
-      Each monitor will use this value plus the Monitor Id to stream
-      content.  So a value of 2000 here will cause a stream for Monitor 1 to
-      hit port 2001.`,
+      Each camera to be streamed must be enabled
+      under its misc tab.`,
     type  =>  $types{integer},
     category  => 'network',
   },