Remove plugin "arp"

The "arp_" plugin is probably a better alternative: it uses modern linux
tools (iproute2) instead of the "arp" tool.

Closes: #1024

plugins/arp/arp

@@ -1,42 +0,0 @@
-#!/bin/sh
-#
-# Plugin to monitor total ARP entries
-#
-#  Parameters understood:
-#
-#      config   (required)
-#      autoconf (optional)
-#
-#  Made by Sven Hartge (sven AT svenhartge DOT de)
-#
-
-#%# family=contrib
-#%# capabilities=autoconf
-
-if [ "$1" = "autoconf" ]; then
-    # Search for arp
-    if which arp >/dev/null; then
-        echo yes
-    else
-        echo "no (missing 'arp' executable)"
-    fi
-    exit 0
-fi
-
-
-
-if [ "$1" = "config" ]; then
-        echo 'graph_title ARP entries'
-        echo 'graph_args --base 1000 -l 0'
-        echo 'graph_vlabel Entries'
-        echo 'graph_category network'
-	echo 'graph_scale no'
-        echo 'graph_info This graph shows the number of ARP entries registered by the system.'
-	echo 'entries.label ARP entries'
-	echo 'entries.draw LINE2'
-	echo 'entries.type GAUGE'
-	echo 'entries.info Number of ARP entries'
-	exit 0
-fi
-
-arp -an | awk 'BEGIN { regex="<incomplete>";} { if (!match($4,regex)) { a[$4] }} END{for(i in a){n++};print "entries.value " n}'