Comment 11 for bug 1251054

$ uname -r
3.13.0-36-generic

$ apt-cache policy network-manager
network-manager:
  Installed: 0.9.8.8-0ubuntu7
  Candidate: 0.9.8.8-0ubuntu7
  Version table:
 *** 0.9.8.8-0ubuntu7 0
        500 http://archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages
        100 /var/lib/dpkg/status

*-network
       description: Wireless interface
       product: Centrino Wireless-N 1000 [Condor Peak]
       vendor: Intel Corporation

$ lsmod | grep wifi
iwlwifi 169932 1 iwldvm
cfg80211 484040 3 iwlwifi,mac80211,iwldvm

sudo killall NetworkManager
or
sudo kill PIDofNetworkManager

works for me as well.