Use libsecp256k1 instead of openssl for crypto.

We still use openssl for bignums (base58) and for ripemd.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

test-cli/create-close-tx.c

@@ -16,7 +16,6 @@
 #include "close_tx.h"
 #include "find_p2sh_out.h"
 #include "protobuf_convert.h"
-#include <openssl/ec.h>
 #include <unistd.h>
 
 int main(int argc, char *argv[])