Try to lift requirement for sprout params

src/init.cpp

@@ -1,5 +1,6 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2014 The Bitcoin Core developers
+// Copyright (c) 2019      The Hush developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
@@ -752,15 +753,11 @@ static void ZC_LoadParams(
     struct timeval tv_start, tv_end;
     float elapsed;
 
-    boost::filesystem::path pk_path = ZC_GetParamsDir() / "sprout-proving.key";
-    boost::filesystem::path vk_path = ZC_GetParamsDir() / "sprout-verifying.key";
     boost::filesystem::path sapling_spend = ZC_GetParamsDir() / "sapling-spend.params";
     boost::filesystem::path sapling_output = ZC_GetParamsDir() / "sapling-output.params";
     boost::filesystem::path sprout_groth16 = ZC_GetParamsDir() / "sprout-groth16.params";
 
     if (!(
-        boost::filesystem::exists(pk_path) &&
-        boost::filesystem::exists(vk_path) &&
         boost::filesystem::exists(sapling_spend) &&
         boost::filesystem::exists(sapling_output) &&
         boost::filesystem::exists(sprout_groth16)
@@ -775,18 +772,17 @@ static void ZC_LoadParams(
         return;
     }
 
-    LogPrintf("Loading verifying key from %s\n", vk_path.string().c_str());
+    //LogPrintf("Loading verifying key from %s\n", vk_path.string().c_str());
     gettimeofday(&tv_start, 0);
 
-    pzcashParams = ZCJoinSplit::Prepared(vk_path.string(), pk_path.string());
+    //pzcashParams = ZCJoinSplit::Prepared(vk_path.string(), pk_path.string());
 
     gettimeofday(&tv_end, 0);
     elapsed = float(tv_end.tv_sec-tv_start.tv_sec) + (tv_end.tv_usec-tv_start.tv_usec)/float(1000000);
     LogPrintf("Loaded verifying key in %fs seconds.\n", elapsed);
 
-    static_assert(
-        sizeof(boost::filesystem::path::value_type) == sizeof(codeunit),
-        "librustzcash not configured correctly");
+    static_assert( sizeof(boost::filesystem::path::value_type) == sizeof(codeunit), "librustzcash not configured correctly");
+
     auto sapling_spend_str = sapling_spend.native();
     auto sapling_output_str = sapling_output.native();
     auto sprout_groth16_str = sprout_groth16.native();
@@ -796,6 +792,7 @@ static void ZC_LoadParams(
     LogPrintf("Loading Sapling (Sprout Groth16) parameters from %s\n", sprout_groth16.string().c_str());
     gettimeofday(&tv_start, 0);
 
+    // TODO: Unfortunately there is no way to initialize things without groth16, unless Rust code is modified.
     librustzcash_init_zksnark_params(
         reinterpret_cast<const codeunit*>(sapling_spend_str.c_str()),
         sapling_spend_str.length(),