Makefile: add target to list running VMs in VirtualBox
Makefile: add target to list running VMs in VirtualBox

    $ make vps
    VBoxManage list runningvms
    "default" {a18b9117-78d7-4506-ba39-cdb069bdc58c}
    "cilium_cilium-master_1494337266676_16697" {c854e14e-68df-49d9-ab2c-7cb96c1d8ee0}

Signed-off-by: Alexander Alemayhu <e46fc836cca3acec03944314d1457c2ae6c68ef3@alemayhu.com>

tklauser/cilium,mskarbek/cilium,tgraf/cilium,tklauser/cilium,tgraf/cilium,cilium/cilium,mskarbek/cilium,tgraf/cilium,tgraf/cilium,scanf/cilium,tgraf/cilium,cilium-team/cilium,tgraf/cilium,gumpt/cilium,cilium/cilium,gumpt/cilium,cilium-team/cilium,michi-covalent/cilium,scanf/cilium,michi-covalent/cilium,gumpt/cilium,eloycoto/cilium,scanf/cilium,scanf/cilium,gumpt/cilium,michi-covalent/cilium,eloycoto/cilium,eloycoto/cilium,cilium/cilium,mskarbek/cilium,gumpt/cilium,scanf/cilium,eloycoto/cilium,mskarbek/cilium,scanf/cilium,mskarbek/cilium,tklauser/cilium,eloycoto/cilium,mskarbek/cilium,scanf/cilium,tklauser/cilium,cilium/cilium,eloycoto/cilium,gumpt/cilium,michi-covalent/cilium,gumpt/cilium,eloycoto/cilium,cilium/cilium,tklauser/cilium,michi-covalent/cilium