Fix androidx-packager attempt #3

This CL makes fetch_all_androidx.py pass in a path relative to the
current working directory instead of a path relative to the chromium src
for fetch_all.py's --android-deps-dir argument.

BUG=1064277

Change-Id: I01ad71331f33c7c0925f005dfe7eaac4a5b1be74
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2491523Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Commit-Queue: Peter Kotwicz <pkotwicz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#819860}

third_party/androidx/fetch_all_androidx.py

@@ -208,8 +208,8 @@ def main():
                           androidx_snapshot_repository_url)
 
     fetch_all_cmd = [
-        _FETCH_ALL_PATH, '--android-deps-dir',
-        os.path.join('third_party', 'androidx'), '--ignore-vulnerabilities'
+        _FETCH_ALL_PATH, '--android-deps-dir', _ANDROIDX_PATH,
+        '--ignore-vulnerabilities'
     ]
     subprocess.run(fetch_all_cmd, check=True)