message: wallet: Make sure no WalletDescriptor members are uninitialized after construction
diff: @@ -92,10 +92,10 @@ class WalletDescriptor
  {
  public:
  std::shared_ptr<Descriptor> descriptor;
  - uint64_t creation_time;
  - int32_t range_start; // First item in range; start of range, inclusive, i.e. [range_start, range_end). This never changes.
  - int32_t range_end; // Item after the last; end of range, exclusive, i.e. [range_start, range_end). This will increment with each TopUp()
  - int32_t next_index; // Position of the next item to generate
  + uint64_t creation_time = 0;
  + int32_t range_start = 0; // First item in range; start of range, inclusive, i.e. [range_start, range_end). This never changes.
  + int32_t range_end = 0; // Item after the last; end of range, exclusive, i.e. [range_start, range_end). This will increment with each TopUp()
  + int32_t next_index = 0; // Position of the next item to generate
  DescriptorCache cache;
  ADD_SERIALIZE_METHODS;
  