scm: Check for cmsg not to be truncated when receiving fds
scm: Check for cmsg not to be truncated when receiving fds

Otherwise we can get stuck waiting for more data in vain.

Signed-off-by: Pavel Emelyanov <c9a32589e048e044184536f7ac71ef92fe82df3e@parallels.com>

biddyweb/criu,tych0/criu,rentzsch/criu,gonkulator/criu,KKoukiou/criu-remote,kawamuray/criu,biddyweb/criu,wtf42/criu,ldu4/criu,LK4D4/criu,eabatalov/criu,sdgdsffdsfff/criu,eabatalov/criu,gonkulator/criu,fbocharov/criu,wtf42/criu,AuthenticEshkinKot/criu,KKoukiou/criu-remote,AuthenticEshkinKot/criu,AuthenticEshkinKot/criu,eabatalov/criu,rentzsch/criu,efiop/criu,efiop/criu,wtf42/criu,AuthenticEshkinKot/criu,tych0/criu,ldu4/criu,marcosnils/criu,KKoukiou/criu-remote,svloyso/criu,eabatalov/criu,eabatalov/criu,fbocharov/criu,AuthenticEshkinKot/criu,gablg1/criu,LK4D4/criu,LK4D4/criu,LK4D4/criu,tych0/criu,kawamuray/criu,ldu4/criu,marcosnils/criu,KKoukiou/criu-remote,svloyso/criu,gablg1/criu,sdgdsffdsfff/criu,fbocharov/criu,ldu4/criu,AuthenticEshkinKot/criu,marcosnils/criu,tych0/criu,marcosnils/criu,fbocharov/criu,gonkulator/criu,sdgdsffdsfff/criu,gablg1/criu,svloyso/criu,rentzsch/criu,ldu4/criu,LK4D4/criu,biddyweb/criu,gablg1/criu,efiop/criu,fbocharov/criu,sdgdsffdsfff/criu,gonkulator/criu,marcosnils/criu,wtf42/criu,kawamuray/criu,KKoukiou/criu-remote,gonkulator/criu,efiop/criu,tych0/criu,KKoukiou/criu-remote,biddyweb/criu,svloyso/criu,kawamuray/criu,fbocharov/criu,efiop/criu,biddyweb/criu,ldu4/criu,svloyso/criu,eabatalov/criu,wtf42/criu,gonkulator/criu,wtf42/criu,LK4D4/criu,efiop/criu,sdgdsffdsfff/criu,marcosnils/criu,gablg1/criu,biddyweb/criu,rentzsch/criu,kawamuray/criu,rentzsch/criu,rentzsch/criu,tych0/criu,gablg1/criu,kawamuray/criu,sdgdsffdsfff/criu,svloyso/criu