qemu-dm-wrapper: fix setrlimit when the existing hardlimit is < our proposed soft limit
qemu-dm-wrapper: fix setrlimit when the existing hardlimit is < our proposed soft limit

Patch provided by James Bulpin <james.bulpin@citrix.com>

fixes xen-org/xenopsd#1

euanh/xenopsd,cheng--zhang/xenopsd,thomassa/xenopsd,koushikcgit/xenopsd,djs55/xenopsd-previous,djs55/xenopsd-previous,thomassa/xenopsd,johnelse/xenopsd,cheng--zhang/xenopsd,euanh/xenopsd,djs55/xenopsd,johnelse/xenopsd,djs55/xenopsd,euanh/xenopsd,djs55/xenopsd,simonjbeaumont/xenopsd,koushikcgit/xenopsd,simonjbeaumont/xenopsd,djs55/xenopsd-previous,thomassa/xenopsd,koushikcgit/xenopsd,cheng--zhang/xenopsd,simonjbeaumont/xenopsd,johnelse/xenopsd