small cleanups in the state code

ensure that variables are initialized. remove unused variables.
provide additional information for state exeception

Signed-off-by: Mic Bowman <mic.bowman@intel.com>

Author: cmickeyb

common/state/basic_kv.h

@@ -23,9 +23,6 @@ namespace state
 {
     class Basic_KV
     {
-    protected:
-        void* handle;
-
     public:
         virtual ~Basic_KV() {}
         virtual void Finalize(ByteArray& id) = 0;

common/state/data_node_io.cpp

@@ -59,8 +59,10 @@ void pstate::data_node_io::init_append_data_node()
 
 void pstate::data_node_io::add_and_init_append_data_node()
 {
-    pdo::error::ThrowIf<pdo::error::RuntimeError>(append_dn_->free_bytes() == data_node::data_end_index() - data_node::data_begin_index(),
-        "appending new data node after empty one");
+    pdo::error::ThrowIf<pdo::error::RuntimeError>(
+        append_dn_->free_bytes() == data_node::data_end_index() - data_node::data_begin_index(),
+        "appending new data node after empty one; %u bytes in block %u",
+        append_dn_->free_bytes(), append_dn_->get_block_num());
 
     unsigned int append_data_node_block_num = block_warehouse_.get_last_block_num();
 

common/state/data_node_io.h

@@ -28,7 +28,9 @@ namespace state
         data_node* append_dn_;
         Cache cache_;
 
-        data_node_io(const ByteArray& key) : block_warehouse_(key), cache_(block_warehouse_) {}
+        data_node_io(const ByteArray& key) :
+            block_warehouse_(key), cache_(block_warehouse_)  { append_dn_ = nullptr; }
+
         void initialize(pdo::state::StateNode& node);
 
         void init_append_data_node();