driver: httpvideodriver: fix import order

Signed-off-by: Bastian Krause <bst@pengutronix.de>

Author: Bastian-Krause

labgrid/driver/httpvideodriver.py

@@ -1,8 +1,9 @@
 # pylint: disable=no-member
 import subprocess
-import attr
 from urllib.parse import urlsplit, urlunsplit
 
+import attr
+
 from .common import Driver
 from ..factory import target_factory
 from ..util.proxy import proxymanager