RPM post remove script update for proper handle on all Linux distributions (#1381)

scripts/post-remove.sh

@@ -15,32 +15,28 @@ function disable_chkconfig {
     rm -f /etc/init.d/telegraf
 }
 
-if [[ -f /etc/redhat-release ]]; then
-    # RHEL-variant logic
-    if [[ "$1" = "0" ]]; then
-	# InfluxDB is no longer installed, remove from init system
-	rm -f /etc/default/telegraf
-	
-	which systemctl &>/dev/null
-	if [[ $? -eq 0 ]]; then
-	    disable_systemd
-	else
-	    # Assuming sysv
-	    disable_chkconfig
-	fi
+if [[ "$1" == "0" ]]; then
+    # RHEL and any distribution that follow RHEL, Amazon Linux covered
+    # telegraf is no longer installed, remove from init system
+    rm -f /etc/default/telegraf
+
+    which systemctl &>/dev/null
+    if [[ $? -eq 0 ]]; then
+        disable_systemd
+    else
+        # Assuming sysv
+        disable_chkconfig
     fi
-elif [[ -f /etc/debian_version ]]; then
+elif [ "$1" == "remove" -o "$1" == "purge" ]; then
     # Debian/Ubuntu logic
-    if [[ "$1" != "upgrade" ]]; then
-	# Remove/purge
-	rm -f /etc/default/telegraf
-	
-	which systemctl &>/dev/null
-	if [[ $? -eq 0 ]]; then
-	    disable_systemd
-	else
-	    # Assuming sysv
-	    disable_update_rcd
-	fi
+    # Remove/purge
+    rm -f /etc/default/telegraf
+
+    which systemctl &>/dev/null
+    if [[ $? -eq 0 ]]; then
+        disable_systemd
+    else
+        # Assuming sysv
+        disable_update_rcd
     fi
 fi