Fix segment coding mismatch for HDR (delta qp)

m_bEncodeDQP was not reset at the beginning of a new CTU. This could lead to wrong cost calculation
in following CTUs. Especially it caused a mismatch in segment based coding.

source/Lib/TLibEncoder/TEncCu.cpp

@@ -233,6 +233,7 @@ Void TEncCu::compressCtu( TComDataCU* pCtu )
   // initialize CU data
   m_ppcBestCU[0]->initCtu( pCtu->getPic(), pCtu->getCtuRsAddr() );
   m_ppcTempCU[0]->initCtu( pCtu->getPic(), pCtu->getCtuRsAddr() );
+  m_bEncodeDQP         = false;
 
   // analysis of CU
   DEBUG_STRING_NEW(sDebug)