init:fix gn format

Signed-off-by: NMupceet <laiguizhong@huawei.com>
Change-Id: I6db4e98bdee247db3daf466823fb88bd02688760

test/exec_test/BUILD.gn

@@ -47,8 +47,7 @@ ohos_executable("fd_holder_test") {
 }
 
 ohos_prebuilt_etc("fd_holder_test.cfg") {
-  source =
-      "//base/startup/init_lite/test/exec_test/fd_holder_test.cfg"
+  source = [ "//base/startup/init_lite/test/exec_test/fd_holder_test.cfg" ]
   part_name = "init"
   module_install_dir = "etc/init"
 }