update_engine: fix english

Fix the english for accuracy regarding DLC.

BUG=chromium:897882
TEST=None

Change-Id: I72ab9ecb7903bb5fb35597222cd7c8b1f4244cfc
Reviewed-on: https://chromium-review.googlesource.com/1351359
Commit-Ready: Xiaochu Liu <xiaochu@chromium.org>
Tested-by: Xiaochu Liu <xiaochu@chromium.org>
Reviewed-by: Amin Hassani <ahassani@chromium.org>
diff --git a/common_service.cc b/common_service.cc
index 213267c..6420b65 100644
--- a/common_service.cc
+++ b/common_service.cc
@@ -106,8 +106,9 @@
 
 bool UpdateEngineService::AttemptInstall(brillo::ErrorPtr* error,
                                          const string& omaha_url,
-                                         const vector<string>& dlc_ids) {
-  if (!system_state_->update_attempter()->CheckForInstall(dlc_ids, omaha_url)) {
+                                         const vector<string>& dlc_module_ids) {
+  if (!system_state_->update_attempter()->CheckForInstall(dlc_module_ids,
+                                                          omaha_url)) {
     // TODO(xiaochu): support more detailed error messages.
     LogAndSetError(error, FROM_HERE, "Could not schedule install operation.");
     return false;