Revert "Add more git tracing."

This reverts commit 1e4dbf3f.

Reason for revert: unlikely but possible cause of http://shortn/_sgL4PqICVB

Original change's description:
> Add more git tracing.
> 
> This CL adds more perf tracing to `git fetch` from bot_update.py and
> git_cache.py
> 
> Change-Id: I9b69c60b6c81fc0c5f23f82fcc889b4d45a27556
> Recipe-Nontrivial-Roll: build_limited_scripts_slave
> Recipe-Nontrivial-Roll: build
> Recipe-Nontrivial-Roll: infra
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1888433
> Reviewed-by: Andrii Shyshkalov <tandrii@google.com>
> Commit-Queue: Erik Chen <erikchen@chromium.org>
> Auto-Submit: Erik Chen <erikchen@chromium.org>

TBR=danakj@chromium.org,tandrii@google.com,erikchen@chromium.org

Change-Id: I03b33bf1532212f83a6b89b1de32fafb6b8aafc4
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1891001Reviewed-by: John Budorick <jbudorick@chromium.org>
Commit-Queue: John Budorick <jbudorick@chromium.org>

git_cache.py

@@ -552,6 +552,14 @@ class Mirror(object):
       spec = spec.decode()
       try:
         self.print('Fetching %s' % spec)
+        env = os.environ.copy()
+        env.update({
+            'GIT_TRACE_PACKET': '1',
+            'GIT_TR2_EVENT': '1',
+            'GIT_TRACE2_EVENT': '1',
+            'GIT_TRACE_CURL': '1',
+            'GIT_TRACE_CURL_NO_DATA': '1'
+        })
         # Only print first 30000 packets. We can use nonlocal keyword once we
         # switch to python 3.
         packet_count = [0]
@@ -570,6 +578,7 @@ class Mirror(object):
               fetch_cmd + [spec],
               cwd=rundir,
               retry=True,
+              env=env,
               filter_fn=FilterPacket)
       except subprocess.CalledProcessError:
         if spec == '+refs/heads/*:refs/heads/*':

recipes/recipe_modules/bot_update/resources/bot_update.py

@@ -666,11 +666,6 @@ def _git_checkout(sln, sln_dir, revisions, refs, git_cache_dir, cleanup_dir):
     env = {
         'GIT_TRACE': 'true',
         'GIT_TRACE_PERFORMANCE': 'true',
-        'GIT_TRACE_PACKET': '1',
-        'GIT_TRACE2_EVENT': '1',
-        'GIT_TRACE_CURL': '1',
-        'GIT_TRACE_CURL_NO_DATA': '1',
-        'INFRA_GIT_WRAPPER_TRACE': '1',
     }
 
   # Step 1: populate/refresh cache, if necessary.
@@ -728,11 +723,11 @@ def _git_checkout(sln, sln_dir, revisions, refs, git_cache_dir, cleanup_dir):
       else:
         _git_disable_gc(sln_dir)
         git('remote', 'set-url', 'origin', mirror_dir, cwd=sln_dir)
-        git('fetch', 'origin', cwd=sln_dir, env=env)
+        git('fetch', 'origin', cwd=sln_dir)
       git('remote', 'set-url', '--push', 'origin', url, cwd=sln_dir)
       for ref in refs:
         refspec = '%s:%s' % (ref, ref.lstrip('+'))
-        git('fetch', 'origin', refspec, cwd=sln_dir, env=env)
+        git('fetch', 'origin', refspec, cwd=sln_dir)
 
       # Windows sometimes has trouble deleting files.
       # This can make git commands that rely on locks fail.