pow: GetNextWorkRequired never called with NULL pindexLast

src/pow.cpp

@@ -12,12 +12,9 @@
 
 unsigned int GetNextWorkRequired(const CBlockIndex* pindexLast, const CBlockHeader *pblock, const Consensus::Params& params)
 {
+    assert(pindexLast != NULL);
     unsigned int nProofOfWorkLimit = UintToArith256(params.powLimit).GetCompact();
 
-    // Genesis block
-    if (pindexLast == NULL)
-        return nProofOfWorkLimit;
-
     // Only change once per difficulty adjustment interval
     if ((pindexLast->nHeight+1) % params.DifficultyAdjustmentInterval() != 0)
     {