download_from_google_storage: Do not call decode() on a string twice
download_from_google_storage: Do not call decode() on a string twice

This throws an exception when running with Python 3:

Exception in thread Thread-1:
Traceback (most recent call last):
  File "/usr/lib/python3.7/threading.py", line 926, in _bootstrap_inner
    self.run()
  File "/usr/lib/python3.7/threading.py", line 870, in run
    self._target(*self._args, **self._kwargs)
  File "/home/rakuco/src/depot_tools/download_from_google_storage.py", line 259, in _downloader_worker_thread
    file_url = '%s/%s' % (base_url, input_sha1_sum.decode())
AttributeError: 'str' object has no attribute 'decode'

We are already calling bytes.decode() in enumerate_input(), whose output
is passed to _downloader_worker_thread().

Bug: 984182, 1007872
Change-Id: I55c4835192caf69a8dee9e89ae1bb5531f4bacae
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1844832
Auto-Submit: Raphael Kubo da Costa <5fe4d20cf6ab8a2cf4e5e71d4c2d58346e96df0d@intel.com>
Commit-Queue: Edward Lesmes <d05609f027dc667cc37492b1dc1bdea5d60fa82a@chromium.org>
Reviewed-by: Edward Lesmes <d05609f027dc667cc37492b1dc1bdea5d60fa82a@chromium.org>

CoherentLabs/depot_tools,CoherentLabs/depot_tools