Fix Archive header check

Signed-off-by: Dan Bailey <danbailey@ilm.com>

Author: danrbailey

openvdb/openvdb/io/Archive.cc

@@ -951,9 +951,9 @@ Archive::readHeader(std::istream& is)
     if (mFileVersion > OPENVDB_FILE_VERSION) {
         OPENVDB_LOG_WARN("unsupported VDB file format (expected version "
             << OPENVDB_FILE_VERSION << " or earlier, got version " << mFileVersion << ")");
-    } else if (mFileVersion < OPENVDB_FILE_VERSION_NODE_MASK_COMPRESSION) {
+    } else if (mFileVersion < OPENVDB_FILE_VERSION_FLOAT_FRUSTUM_BBOX) {
         OPENVDB_THROW(IoError,
-            "VDB file version < 222 (NODE_MASK_COMPRESSION) is no longer supported.");
+            "VDB file version < 221 (FLOAT_FRUSTUM_BBOX) is no longer supported.");
     }
 
     // 3) Read the library version numbers (not stored prior to file format version 211).