Modify namespace to ohos form harmonyos

Change-Id: Ia29013889dd9f784266e06998eb6c61bb37441cc

BUILD.gn

 # Copyright (c) Huawei Technologies Co., Ltd. 2019-2019. All rights reserved.
 
-import("//build/harmonyos.gni")
-import("//build/harmonyos/ndk/ndk.gni")
+import("//build/ohos.gni")
+import("//build/ohos/ndk/ndk.gni")
 
 config("zlib_config") {
   include_dirs = [ "." ]
@@ -50,12 +50,12 @@ static_library("libz_test") {
   deps = [":libz"]
 }
 
-harmonyos_ndk_headers("zlib_header") {
+ohos_ndk_headers("zlib_header") {
   sources = ["./zlib.h","./zconf.h"]
   notices = ["LICENSE"]
 }
 
-harmonyos_ndk_library("libz_ndk") {
+ohos_ndk_library("libz_ndk") {
   output_name = "z"
   ndk_description_file = "./zlib.ndk.json"
 }