Revert "update_engine: Support milestones to EOL from Omaha"

This reverts commit 893cae4b0e5141bcaf9f56b1775e681c8f523630.

Reason for revert: use of EOL date and EOL notification date instead milestones to EOL.

Original change's description:
> update_engine: Support milestones to EOL from Omaha
>
> Initiative to show EOL message on Chrome OS devices require that
> update_engine parses the fields within Omaha response that pertain to the
> new milestones to EOL field. The Omaha response will include a new
> field called "milestones_to_eol" which will be an integer value
> string.
>
> The job of update_engine when it comes to milestones to EOL from Omaha
> is to merely forward. No checks and no modifications of fields are
> done within update_engine besides being able to convert the milestones
> to EOL from a string to integer.
>
> BUG=chromium:994999
> TEST=FEATURES="test" emerge-$BOARD update_engine update_engine-client
> TEST=cros deploy $IP update_engine update_engine-client
> TEST=test_that -b $BOARD $IP autoupdate_EOL # from Cq-Depend
> TEST=test_that -b $BOARD $IP autoupdate_EOL.milestones # from Cq-Depend
>
> Cq-Depend:chromium:1761371
> Change-Id: I268e4c8e641b17d6a727a50f53285cc97c76eb22
> Reviewed-on: https://chromium-review.googlesource.com/1759285
> Tested-by: Jae Hoon Kim <kimjae@chromium.org>
> Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
> Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>
> Reviewed-by: Nicolas Norvez <norvez@chromium.org>
> Reviewed-by: Amin Hassani <ahassani@chromium.org>

TBR=maybelle@chromium.org,norvez@chromium.org,ahassani@chromium.org,abutzier@chromium.org,chromiumos-cl-exonerator@appspot.gserviceaccount.com,kimjae@chromium.org

BUG=chromium:994999
TEST=none
Cq-Depend:chromium:1782971
Change-Id: I42e75e22948b3653500d355027dc3312015c9ebf
Reviewed-on: https://chromium-review.googlesource.com/c/aosp/platform/system/update_engine/+/1782970
Tested-by: Jae Hoon Kim <kimjae@chromium.org>
Commit-Queue: Jae Hoon Kim <kimjae@chromium.org>
Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>
Reviewed-by: Amin Hassani <ahassani@chromium.org>
diff --git a/update_engine_client.cc b/update_engine_client.cc
index 9748c4d..954e856 100644
--- a/update_engine_client.cc
+++ b/update_engine_client.cc
@@ -41,7 +41,6 @@
 
 using chromeos_update_engine::EolStatus;
 using chromeos_update_engine::ErrorCode;
-using chromeos_update_engine::MilestonesToEol;
 using chromeos_update_engine::UpdateEngineStatusToString;
 using chromeos_update_engine::UpdateStatusToString;
 using chromeos_update_engine::utils::ErrorCodeToString;
@@ -560,20 +559,12 @@
   }
 
   if (FLAGS_eol_status) {
-    int eol_status, milestones_to_eol;
-    if (!client_->GetEolStatus(&eol_status, &milestones_to_eol)) {
-      LOG(ERROR) << "Error getting the end-of-life status and milestones to "
-                    "end-of-life.";
+    int eol_status;
+    if (!client_->GetEolStatus(&eol_status)) {
+      LOG(ERROR) << "Error getting the end-of-life status.";
     } else {
       EolStatus eol_status_code = static_cast<EolStatus>(eol_status);
-      MilestonesToEol milestones_to_eol_code = milestones_to_eol;
-      printf(
-          "EOL_STATUS=%s\n"
-          "MILESTONES_TO_EOL=%s\n",
-          EolStatusToString(eol_status_code),
-          chromeos_update_engine::MilestonesToEolToString(
-              milestones_to_eol_code)
-              .c_str());
+      printf("EOL_STATUS=%s\n", EolStatusToString(eol_status_code));
     }
   }