fixup! Add BP++ round 1

Author: sanket1729

src/modules/bppp/bppp_rangeproof_impl.h

@@ -4,8 +4,8 @@
  * file COPYING or http://www.opensource.org/licenses/mit-license.php.*
  **********************************************************************/
 
-#ifndef _SECP256K1_MODULE_BPP_RANGEPROOF_IMPL_
-#define _SECP256K1_MODULE_BPP_RANGEPROOF_IMPL_
+#ifndef SECP256K1_MODULE_BPP_RANGEPROOF_IMPL_
+#define SECP256K1_MODULE_BPP_RANGEPROOF_IMPL_
 
 
 #include "../../group.h"