After an upgrade over a previous version to Ubuntu 14.04 I have problems with connecting to WiFi. After suspending it won't reconnect to any existing network unless I restart the laptop.

sudo lshw -C network:

  *-network               
       description: Ethernet interface
       product: 82567LM Gigabit Network Connection
       vendor: Intel Corporation
       physical id: 19
       bus info: pci@0000:00:19.0
       logical name: eth0
       version: 03
       serial: 00:27:13:b4:d3:58
       capacity: 1Gbit/s
       width: 32 bits
       clock: 33MHz
       capabilities: pm msi bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=e1000e driverversion=2.3.2-k firmware=1.8-3 latency=0 link=no multicast=yes port=twisted pair
       resources: irq:45 memory:fc200000-fc21ffff memory:fc225000-fc225fff ioport:1840(size=32)
  *-network
       description: Wireless interface
       product: PRO/Wireless 5100 AGN [Shiloh] Network Connection
       vendor: Intel Corporation
       physical id: 0
       bus info: pci@0000:03:00.0
       logical name: wlan0
       version: 00
       serial: 00:26:c6:c6:6b:c8
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless
       configuration: broadcast=yes driver=iwlwifi driverversion=3.13.0-29-generic firmware=8.83.5.1 build 33692 ip=10.0.1.160 latency=0 link=yes multicast=yes wireless=IEEE 802.11abgn
       resources: irq:48 memory:f4200000-f4201fff