Add unbound members group access to control key

Recent openssl genrsa does not use umask for generated keys. There is no
strong reason why every member of unbound group should be able read
server key. But control key would be quite useful to be group readable
and to allow control access to whole group. Allowing access to control
by group membership, not via sudo.

smallapp/unbound-control-setup.sh.in

@@ -205,6 +205,7 @@ fi
 chmod o-rw \
       "$SVR_BASE.pem" \
       "$SVR_BASE.key" \
+chmod g+r,o-rw \
       "$CTL_BASE.pem" \
       "$CTL_BASE.key"