package/net-tools: bump to version 2.10

Use standard install target as update target has been removed with
https://sourceforge.net/p/net-tools/code/ci/5484cf9a13a2b1d6f604aad2a4fa41c7f01e1a46/



Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>