BaseTools/VfrCompile: Resolve uninit class variables in constructor

The commit initializes those possibly uninitialized class variables in
class constructors.

Cc: Yonghong Zhu <yonghong.zhu@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>

BaseTools/Source/C/VfrCompile/VfrError.cpp

@@ -67,6 +67,7 @@ CVfrErrorHandle::CVfrErrorHandle (
   mScopeRecordListTail   = NULL;
   mVfrErrorHandleTable   = VFR_ERROR_HANDLE_TABLE;
   mVfrWarningHandleTable = VFR_WARNING_HANDLE_TABLE;
+  mWarningAsError        = FALSE;
 }
 
 CVfrErrorHandle::~CVfrErrorHandle (