$ sudo aptitude -V install x11-common=1:7.4+3ubuntu7
Reading package lists... Done
Building dependency tree
Reading state information... Done
Reading extended state information
Initializing package states... Done
The following packages will be DOWNGRADED:
x11-common [1:7.4+3ubuntu10 -> 1:7.4+3ubuntu7]
Downgrade x11-common helped:
$ sudo aptitude -V install x11-common= 1:7.4+3ubuntu7
Reading package lists... Done
Building dependency tree
Reading state information... Done
Reading extended state information
Initializing package states... Done
The following packages will be DOWNGRADED:
x11-common [1:7.4+3ubuntu10 -> 1:7.4+3ubuntu7]