Fix accrual snapshot heights

Incorrect order of statements caused the snapshot system to store
snapshots with the accrual data for the previous superblock. This
fixes the issue by ordering the statements so that snapshot files
contain the accrual values for the time right up until the height
of the superblock that a snapshot is labeled for.

src/neuralnet/tally.cpp

@@ -264,11 +264,11 @@ class ResearcherTally
         // switch to block version 11.
         //
         if (superblock->m_version >= 2) {
+            TallySuperblockAccrual(superblock.m_timestamp);
+
             if (!m_snapshots.Store(superblock.m_height, m_researchers)) {
                 return false;
             }
-
-            TallySuperblockAccrual(superblock.m_timestamp);
         }
 
         m_current_superblock = std::move(superblock);
@@ -288,8 +288,8 @@ class ResearcherTally
     {
         if (m_current_superblock->m_version >= 2) {
             try {
-                return m_snapshots.ApplyLatest(m_researchers)
-                    && m_snapshots.Drop(m_current_superblock.m_height);
+                return m_snapshots.Drop(m_current_superblock.m_height)
+                    && m_snapshots.ApplyLatest(m_researchers);
             } catch (const SnapshotStateError& e) {
                 LogPrintf("%s: %s", e.what());
 
@@ -312,7 +312,9 @@ class ResearcherTally
     //! \return \c false if the snapshot system failed to initialize because of
     //! an error.
     //!
-    bool ActivateSnapshotAccrual(const CBlockIndex* const pindex)
+    bool ActivateSnapshotAccrual(
+        const CBlockIndex* const pindex,
+        SuperblockPtr superblock)
     {
         // Someone might run one of the snapshot accrual testing RPCs before
         // the chain is synchronized. We allow this after passing version 10
@@ -324,6 +326,7 @@ class ResearcherTally
         }
 
         m_snapshot_baseline_pindex = pindex;
+        m_current_superblock = std::move(superblock);
 
         try {
             if (!m_snapshots.Initialize()) {
@@ -574,7 +577,9 @@ bool Tally::ActivateSnapshotAccrual(const CBlockIndex* const pindex)
     //
     Quorum::CommitSuperblock(pindex->nHeight);
 
-    return g_researcher_tally.ActivateSnapshotAccrual(pindex);
+    return g_researcher_tally.ActivateSnapshotAccrual(
+        pindex,
+        Quorum::CurrentSuperblock());
 }
 
 bool Tally::IsLegacyTrigger(const uint64_t height)