Remove curl verbose printing

R=apolito@google.com, ehmaldonado@chromium.org

Change-Id: Ie453bb95208561a09a5f1f62cb9543e31cbe031f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2171923
Auto-Submit: Josip Sokcevic <sokcevic@google.com>
Reviewed-by: Edward Lesmes <ehmaldonado@chromium.org>
Commit-Queue: Josip Sokcevic <sokcevic@google.com>

recipes/recipe_modules/bot_update/resources/bot_update.py

@@ -716,7 +716,6 @@ def _git_checkout(sln, sln_dir, revisions, refs, no_fetch_tags, git_cache_dir,
   if url == CHROMIUM_SRC_URL or url + '.git' == CHROMIUM_SRC_URL:
     # This is for performance investigation of `git fetch` in chromium/src.
     env = {
-        'GIT_CURL_VERBOSE': '1',
         'GIT_TRACE': 'true',
         'GIT_TRACE_PERFORMANCE': 'true',
     }