rm block_desc.h whitespace

Author: gmcather

paddle/fluid/framework/block_desc.h

@@ -88,7 +88,7 @@ class BlockDesc {
   OpDesc *PrependOp();
 
   void PrependAllocatedOp(std::unique_ptr<OpDesc> &&op_desc);
-  
+
   void RemoveOp(size_t s, size_t e);
 
   std::vector<OpDesc *> AllOps() const;