Fixed a syntax error with python 3.6
Fixed a syntax error with python 3.6

This fixes this error:
raceback (most recent call last):
  File "/usr/bin/electrum", line 98, in <module>
    from electrum import bitcoin, network
  File "/usr/lib/python3.6/site-packages/electrum/__init__.py", line 2, in <module>
    from util import format_satoshis, print_msg, print_error, set_verbosity
  File "/usr/lib/python3.6/site-packages/electrum/util.py", line 537
    except socket.error, err:

Also, other exceptions in this file use the except X as Y syntax.
digitalbitbox/electrum,argentumproject/electrum-arg,fujicoin/electrum-fjc,spesmilo/electrum,dabura667/electrum,kyuupichan/electrum,fireduck64/electrum,dabura667/electrum,pknight007/electrum-vtc,romanz/electrum,vertcoin/electrum-vtc,wakiyamap/electrum-mona,argentumproject/electrum-arg,pooler/electrum-ltc,vertcoin/electrum-vtc,molecular/electrum,fyookball/electrum,asfin/electrum,cryptapus/electrum,digitalbitbox/electrum,vertcoin/electrum-vtc,digitalbitbox/electrum,neocogent/electrum,fujicoin/electrum-fjc,fujicoin/electrum-fjc,romanz/electrum,fireduck64/electrum,dashpay/electrum-dash,cryptapus/electrum,wakiyamap/electrum-mona,spesmilo/electrum,pknight007/electrum-vtc,neocogent/electrum,dashpay/electrum-dash,spesmilo/electrum,kyuupichan/electrum,cryptapus/electrum,pooler/electrum-ltc,neocogent/electrum,romanz/electrum,wakiyamap/electrum-mona,fyookball/electrum,fireduck64/electrum,dashpay/electrum-dash,argentumproject/electrum-arg,fyookball/electrum,molecular/electrum,pooler/electrum-ltc,dashpay/electrum-dash,dabura667/electrum,asfin/electrum,asfin/electrum,digitalbitbox/electrum,vialectrum/vialectrum,molecular/electrum,spesmilo/electrum,pknight007/electrum-vtc,wakiyamap/electrum-mona,molecular/electrum,dabura667/electrum,vertcoin/electrum-vtc,pooler/electrum-ltc,vialectrum/vialectrum,vialectrum/vialectrum,fireduck64/electrum,pknight007/electrum-vtc,argentumproject/electrum-arg,kyuupichan/electrum