Revert "gerrit-util: Fix GCE check from behind proxy."

This reverts commit 9ee86e5a46.

Reason for revert: Typo.

Original change's description:
> gerrit-util: Fix GCE check from behind proxy.
> 
> Setting HTTP_PROXY or HTTPS_PROXY environment variables will cause git cl
> to fail.
> 
> The behavior of an unreachable server behind proxy is different from a direct
> connection, it won't throw a httplib2.ServerNotFoundError error,
> so catch httplib2.Httplib2Error instead.
> 
> Bug: 1050380
> Change-Id: I32e2220483de1fd6222c7fd6063039fb86277ef0
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2050947
> Reviewed-by: Anthony Polito <apolito@google.com>
> Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>

TBR=ehmaldonado@chromium.org,apolito@google.com,infra-scoped@luci-project-accounts.iam.gserviceaccount.com

Change-Id: Idb17520e71fc1d892694e0d4d1cf1630a42bb482
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1050380
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2055390
Reviewed-by: Edward Lesmes <ehmaldonado@chromium.org>
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>

gerrit_util.py

@@ -288,7 +288,8 @@ class GceAuthenticator(Authenticator):
     # Based on https://cloud.google.com/compute/docs/metadata#runninggce
     try:
       resp, _ = cls._get(cls._INFO_URL)
-    except (socket.error, httplib2.Httplib2Error):
+    except (socket.error, httplib2.ServerNotFoundError,
+            httplib2.socks.HTTPError):
       # Could not resolve URL.
       return False
     return resp.get('metadata-flavor') == 'Google'