vnstat: update to v1.16

Updates vnStat to the latest stable version, drops obsolete patches.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

net/vnstat/patches/001-conf.patch

@@ -1,19 +0,0 @@
---- a/cfg/vnstat.conf
-+++ b/cfg/vnstat.conf
-@@ -78,13 +78,13 @@ DaemonUser ""
- DaemonGroup ""
- 
- # how often (in seconds) interface data is updated
--UpdateInterval 30
-+UpdateInterval 60
- 
- # how often (in seconds) interface status changes are checked
--PollInterval 5
-+PollInterval 30
- 
- # how often (in minutes) data is saved to file
--SaveInterval 5
-+SaveInterval 30
- 
- # how often (in minutes) data is saved when all interface are offline
- OfflineSaveInterval 30