utils: increase the FTP timeout

[rgonzalezfluendo]

Fix infra issues with the fridge:

0:02:20.991012 Recipe 'gst-fluendo-mp3dec-1.0' failed at the build step 'upload_binary'
Traceback (most recent call last):
  File "./cerbero/cerbero/build/oven.py", line 249, in _cook_recipe
    _run_step(stepfunc, recipe)
  File "./cerbero/cerbero/build/oven.py", line 235, in _run_step
    stepfunc(*args)
  File "./cerbero/cerbero/build/fridge.py", line 275, in upload_binary
    self.binaries_remote.upload_binary(fetch_package, self.binaries_local,
  File "./cerbero/cerbero/build/fridge.py", line 144, in upload_binary
    with Ftp(self.remote, user=self.username, password=self.password) as ftp:
  File "./cerbero/cerbero/utils/shell.py", line 506, in __init__
    self.ftp.connect(remote.hostname, remote.port or 0)
  File "/usr/lib/python3.8/ftplib.py", line 154, in connect
    self.sock = socket.create_connection((self.host, self.port), self.timeout,
  File "/usr/lib/python3.8/socket.py", line 808, in create_connection
    raise err
  File "/usr/lib/python3.8/socket.py", line 796, in create_connection
    sock.connect(sa)
TimeoutError: [Errno 110] Connection timed out