Fix misspelled Qt.CheckSate attribute

Traceback (most recent call last):
  File "nxdrive/__main__.py", line 118, in main
  File "nxdrive/commandline.py", line 528, in handle
  File "nxdrive/commandline.py", line 563, in launch
  File "nxdrive/commandline.py", line 547, in _get_application
  File "nxdrive/gui/application.py", line 153, in __init__
  File "nxdrive/gui/application.py", line 1546, in show_metrics_acceptance
AttributeError: type object 'Qt' has no attribute 'CheckSate'

2020-02-12 12:05:40 10479 4613057984 INFO     nxdrive.commandline Command line: argv=[], options=Namespace(channel='centralized', debug=False, debug_pydev=False, delay=30, force_locale=None, handshake_timeout=60, locale='en', log_filename=None, log_level_console='WARNING', log_level_file='INFO', max_errors=3, nofscheck=False, nxdrive_home=PosixPath('/Users/tiger-222/.nuxeo-drive'), proxy_server=None, ssl_no_verify=False, sync_and_quit=False, timeout=30, update_check_delay=3600, update_site_url='https://community.nuxeo.com/static/drive-updates')
2020-02-12 12:05:40 10479 4613057984 INFO     nxdrive.commandline Running on version 4.4.2
2020-02-12 12:05:40 10479 4613057984 INFO     nxdrive.commandline SSL support: True
2020-02-12 12:05:40 10479 4613057984 INFO     nxdrive.commandline Enabling faulthandler in PosixPath('/Users/tiger-222/.nuxeo-drive/logs/segfault.log')
2020-02-12 12:05:40 10479 4613057984 INFO     nxdrive.engine.dao.sqlite Create ManagerDAO on PosixPath('/Users/tiger-222/.nuxeo-drive/manager.db')
2020-02-12 12:05:40 10479 4613057984 INFO     nxdrive.engine.dao.sqlite Create main connexion on PosixPath('/Users/tiger-222/.nuxeo-drive/manager.db') (dir_exists=True, file_exists=False)
2020-02-12 12:05:40 10479 4613057984 INFO     nxdrive.manager    OS integration type: macOS
2020-02-12 12:05:40 10479 4613057984 INFO     nxdrive.manager    Proxy configuration is SystemProxy<>
2020-02-12 12:05:40 10479 4613057984 INFO     nxdrive.options    Option 'log_level_file' updated: 'INFO' -> 'INFO' [manual]
2020-02-12 12:05:40 10479 4613057984 DEBUG    nxdrive.options    Options(log_level_file[manual]='INFO')
2020-02-12 12:05:40 10479 4613057984 INFO     nxdrive.options    Option 'channel' updated: 'centralized' -> 'centralized' [local]
2020-02-12 12:05:40 10479 4613057984 DEBUG    nxdrive.options    Options(channel[local]='centralized', log_level_file[manual]='INFO')
2020-02-12 12:05:40 10479 4613057984 INFO     nxdrive.options    Option 'channel' updated: 'centralized' -> 'centralized' [manual]
2020-02-12 12:05:40 10479 4613057984 DEBUG    nxdrive.options    Options(channel[manual]='centralized', log_level_file[manual]='INFO')
2020-02-12 12:05:40 10479 4613057984 DEBUG    nxdrive.manager    Saving the current version (4.4.2) into PosixPath('/Users/tiger-222/.nuxeo-drive/VERSION')
2020-02-12 12:05:40 10479 4613057984 INFO     nxdrive.options    Option 'deletion_behavior' updated: 'unsync' -> 'unsync' [manual]
2020-02-12 12:05:40 10479 4613057984 DEBUG    nxdrive.options    Options(channel[manual]='centralized', deletion_behavior[manual]='unsync', log_level_file[manual]='INFO')
2020-02-12 12:05:41 10479 4613057984 DEBUG    nxdrive.osi.darwin.darwin Sending menu to FinderSync