RunUnderSystemdScope: Wait until scope is started before we return
RunUnderSystemdScope: Wait until scope is started before we return

We need to do this, because otherwise we will continue and exit the
pid before systemd has a chance to look at it.

Signed-off-by: Alexander Larsson <8c32c4b573bb86be9076a894bc9e0dfe2b512e8a@redhat.com>

rhatdan/cri-o,vbatts/cri-o,mikebrow/cri-o,14rcole/cri-o,kubernetes-incubator/ocid,14rcole/cri-o,kubernetes-incubator/cri-o,mikebrow/cri-o,kubernetes-incubator/cri-o,mheon/cri-o,jwhonce/ocid,apilloud/cri-o,kubernetes-incubator/ocid,umohnani8/cri-o,jwhonce/ocid,apilloud/cri-o,vbatts/cri-o,mheon/cri-o,nalind/cri-o,mheon/cri-o,jwhonce/ocid,rhatdan/cri-o,umohnani8/cri-o,vbatts/cri-o,umohnani8/cri-o,rhatdan/cri-o,kubernetes-incubator/ocid,vbatts/cri-o,rhatdan/cri-o,apilloud/cri-o,14rcole/cri-o,mheon/cri-o,mikebrow/cri-o,kubernetes-incubator/cri-o,nalind/cri-o,14rcole/cri-o,umohnani8/cri-o,mikebrow/cri-o,nalind/cri-o,kubernetes-incubator/cri-o