Don't do parallel make
Don't do parallel make

Parallel make doesn't work since some VRs are built with a temporary container
and that has the static name of vr-temp which leads to a collision.

holmahenkel/vrnetlab,mzagozen/vrnetlab,bdreisbach/vrnetlab,plajjan/vrnetlab,plajjan/vrnetlab,mzagozen/vrnetlab,bdreisbach/vrnetlab,holmahenkel/vrnetlab