package/netsnmp: fix legal info

Commit 87bef179222e wrongly removed hash of COPYING

Fixes: 87bef179222ee8a0b0f39c8f96113a4ecf813085

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
(cherry picked from commit dfa4a4dd2a9495ac7aabefb7c45f2c74bf1eab2e)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/netsnmp/netsnmp.hash

@@ -2,3 +2,6 @@
 # https://sourceforge.net/projects/net-snmp/files/net-snmp/5.9/net-snmp-5.9.tar.gz.asc
 # using key D0F8F495DA6160C44EFFBF10F07B9D2DACB19FD6
 sha256  04303a66f85d6d8b16d3cc53bde50428877c82ab524e17591dfceaeb94df6071  net-snmp-5.9.tar.gz
+
+# Hash for license file
+sha256  ed869ea395a1f125819a56676385ab0557a21507764bf56f2943302011381e59  COPYING