Clean up pick_random_server() and filter_protocol() and their

call sites.

Remove unused imports and redundant random pick of server

gui/gtk.py

@@ -34,7 +34,6 @@ import platform
 MONOSPACE_FONT = 'Lucida Console' if platform.system() == 'Windows' else 'monospace'
 
 from electrum.util import format_satoshis, parse_URI
-from electrum.network import DEFAULT_SERVERS
 from electrum.bitcoin import MIN_RELAY_TX_FEE
 
 def numbify(entry, is_int = False):

gui/qt/network_dialog.py

@@ -23,7 +23,7 @@ import os.path, json, ast, traceback
 
 from PyQt4.QtGui import *
 from PyQt4.QtCore import *
-from electrum import DEFAULT_SERVERS, DEFAULT_PORTS
+from electrum import DEFAULT_PORTS
 
 from util import *