VirtualBox 4.3.26 and Centos-7 guest

[brunotag]

I updated to VirtualBox 4.3.26 and installed the corresponding extension.
My Centos-7 guest has lost the network connection.
Other guests work correctly.

I checked the status of NetworkManager, and this is the output:

systemctl status NetworkManager.service -l
NetworkManager.service - Network Manager
Loaded: loaded (/usr/lib/systemd/system/NetworkManager.service; enabled)
Active: active (running) since Tue 2015-03-17 11:34:07 CET; 15min ago
Main PID: 705 (NetworkManager)
CGroup: /system.slice/NetworkManager.service
└─705 /usr/sbin/NetworkManager --no-daemon

Mar 17 11:35:07 mario-centos7 NetworkManager[705]: <info> NetworkManager state is now DISCONNECTING
Mar 17 11:35:07 mario-centos7 NetworkManager[705]: <info> NetworkManager state is now DISCONNECTED
Mar 17 11:35:45 mario-centos7 systemd[1]: Started Network Manager.
Mar 17 11:42:15 mario-centos7 NetworkManager[705]: ifcfg-rh: parsing /etc/sysconfig/network-scripts/ifcfg-lo ...
Mar 17 11:42:15 mario-centos7 NetworkManager[705]: ifcfg-rh: parsing /etc/sysconfig/network-scripts/ifcfg-lo ...
Mar 17 11:42:15 mario-centos7 NetworkManager[705]: ifcfg-rh: parsing /etc/sysconfig/network-scripts/ifcfg-lo ...
Mar 17 11:42:16 mario-centos7 NetworkManager[705]: ifcfg-rh: parsing /etc/sysconfig/network-scripts/ifcfg-lo ...
Mar 17 11:42:16 mario-centos7 NetworkManager[705]: <warn> Failed to activate 'enp0s3': Connection 'enp0s3' is not available on the device enp0s3 at this time.
Mar 17 11:42:16 mario-centos7 NetworkManager[705]: <info> NetworkManager state is now DISCONNECTING
Mar 17 11:42:16 mario-centos7 NetworkManager[705]: <info> NetworkManager state is now DISCONNECTED

[brunotag]

For a mysterious reason the guest option Settings->Network->Advanced->Cable Connected was unchecked.
Checking the option solves the problem.