update_engine: Remove GPIO support.

We have not used GPIO since Jan 2013. This CL removes the GPIO handling code.
As a side effect, it also removes dependency on libudev.

BUG=chromium:221725
CQ-DEPEND=CL:199683
TEST=unittest
TEST=AU end2end test on real device from older version to a version that
has CL applied, then from that to another newer version (need not have
this CL applied).

Change-Id: I4352488ec360b44a44b137c40a3ae4ec35c6fe9d
Reviewed-on: https://chromium-review.googlesource.com/199626
Reviewed-by: Gilad Arnold <garnold@chromium.org>
Commit-Queue: Nam Nguyen <namnguyen@chromium.org>
Tested-by: Nam Nguyen <namnguyen@chromium.org>
diff --git a/libcurl_http_fetcher.cc b/libcurl_http_fetcher.cc
index 886a446..2c3fd4d 100644
--- a/libcurl_http_fetcher.cc
+++ b/libcurl_http_fetcher.cc
@@ -192,16 +192,16 @@
                             kDownloadMaxRedirects),
            CURLE_OK);
 
-  // If we are running in test mode or using a dev/test build, then lock down
-  // the appropriate curl options for HTTP or HTTPS depending on the url.
-  if (!is_test_mode_ && GetSystemState()->hardware()->IsOfficialBuild()) {
+  // Lock down the appropriate curl options for HTTP or HTTPS depending on
+  // the url.
+  if (GetSystemState()->hardware()->IsOfficialBuild()) {
     if (StartsWithASCII(url_to_use, "http://", false))
       SetCurlOptionsForHttp();
     else
       SetCurlOptionsForHttps();
   } else {
-    LOG(INFO) << "Not setting http(s) curl options because we are in "
-              << "test mode or running a dev/test image";
+    LOG(INFO) << "Not setting http(s) curl options because we are "
+              << "running a dev/test image";
   }
 
   CHECK_EQ(curl_multi_add_handle(curl_multi_handle_, curl_handle_), CURLM_OK);