HPCC-21049 Remove local variable no longer required

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>

thorlcr/activities/hashdistrib/thhashdistribslave.cpp

@@ -606,7 +606,6 @@ protected:
         }
         void closeWrite()
         {
-            unsigned i;
             CMessageBuffer nullMsg;
             for (unsigned dest=0; dest<owner.numnodes; dest++)
             {