ndb - bug#29057 bug#29067 and bug#29118

  Fix 3 problems in REDO validation that could(will) lead to "Error while reading REDO log"


ndb/src/kernel/blocks/dblqh/Dblqh.hpp:
  add new state
ndb/src/kernel/blocks/dblqh/DblqhMain.cpp:
  fix bugs + add debugging

ndb/src/kernel/blocks/dblqh/Dblqh.hpp

@@ -1617,7 +1617,8 @@ public:
       ACTIVE_WRITE_LOG = 17,             ///< A write operation during 
                                         ///< writing of log
       READ_SR_INVALIDATE_PAGES = 18,
-      WRITE_SR_INVALIDATE_PAGES = 19
+      WRITE_SR_INVALIDATE_PAGES = 19,
+      WRITE_SR_INVALIDATE_PAGES_UPDATE_PAGE0 = 20
     };
     /**
      * We have to remember the log pages read. 
@@ -2437,7 +2438,7 @@ private:
   void errorReport(Signal* signal, int place);
   void warningReport(Signal* signal, int place);
   void invalidateLogAfterLastGCI(Signal *signal);
-  void readFileInInvalidate(Signal *signal);
+  void readFileInInvalidate(Signal *signal, bool stepNext);
   void exitFromInvalidate(Signal* signal);
   Uint32 calcPageCheckSum(LogPageRecordPtr logP);