modify for pr=17924 (#886)

* new flags documents

* flags

* flags

* flags

* modify for PR=17924

* modify for pr=17924

* modify for pr=17924

doc/fluid/flags_cn.rst

 
-Flags
+==================
+环境变量FLAGS
 ==================
 
 
@@ -443,21 +444,6 @@ Int32型，缺省值为3。
 FLAGS_fuse_parameter_groups_size=3 - 将单组参数的梯度大小设为3。
 
 
-fuse_parameter_memory_size
-*******************************************
-(始于1.4.0)
-
-FLAGS_fuse_parameter_memory_size表示作为通信调用输入（例如NCCLAllReduce）的单组参数梯度的上限内存大小。默认值为0，表示不根据memory_size设置组。单位是字节。
-
-取值范围
----------------
-Uint64型，缺省值为0。
-
-示例
--------
-FLAGS_fuse_parameter_memory_size=131072 - 将单组参数梯度的上限大小设为131072字节。
-
-
 init_allocated_mem
 *******************************************
 (始于0.15.0)

doc/fluid/flags_en.rst

 ==================
-Flags
+FLAGS
 ==================
 
 allocator_strategy
@@ -443,21 +443,6 @@ Example
 FLAGS_fuse_parameter_groups_size=3 will set the size of one group parameters' gradient to 3.
 
 
-fuse_parameter_memory_size
-*******************************************
-(since 1.4.0)
-
-FLAGS_fuse_parameter_memory_size indicates the up limited memory size of one group parameters' gradient which is the input of communication calling ( e.g NCCLAllReduce). The default value is 0, it means that not set group according to memory_size. The unit is byte.
-
-Values accepted
----------------
-Uint64. The default value is 0.
-
-Example
--------
-FLAGS_fuse_parameter_memory_size=131072 set the up limited memory size of one group parameters' gradient to 131072 bytes.
-
-
 init_allocated_mem
 *******************************************
 (since 0.15.0)