Install qemu-kvm instead of kvm package on Ubuntu

Since at least 12.04, the kvm package is a transitional dummy
package intended to move users to the newer qemu-kvm package.  This
removes the dependency on this dummy package, which will be going away
in 14.04, and instead depends on the proper qemu-kvm package.

Change-Id: I4a88ada3cf32106413a9fae6fe77c9c4c28a524e
Closes-bug: #1294557
Merge "Install qemu-kvm instead of kvm package on Ubuntu"