docker: Set explicit --network for lighting-cli

This should not be needed because we're specifying the exact --rpc-file
to use, but c-lightning issues a (non-fatal) "please set network=testnet
in config!" warning without this.

Author: shesek

bin/docker-entrypoint.sh

@@ -75,7 +75,7 @@ fi
 sleep 0.5
 
 if command -v lightning-cli > /dev/null; then
-  lightning-cli --rpc-file=$LN_NET_PATH/lightning-rpc getinfo > /dev/null
+  lightning-cli --rpc-file=$LN_NET_PATH/lightning-rpc --network=$NETWORK getinfo > /dev/null
   echo -n "c-lightning RPC ready."
 fi