Add an additional argument to libcloud.compute.drivers.GCENodeDriver.create_node to allow for creation of preemptible GCE instances
Add an additional argument to libcloud.compute.drivers.GCENodeDriver.create_node to allow for creation of preemptible GCE instances

Signed-off-by: Anthony Shaw <1bb2a1c4994a69c577688ea8868f94e36f081e42@gmail.com>
Closes #643

supertom/libcloud,vongazman/libcloud,pquentin/libcloud,mathspace/libcloud,wrigri/libcloud,vongazman/libcloud,watermelo/libcloud,curoverse/libcloud,techhat/libcloud,ZuluPro/libcloud,NexusIS/libcloud,curoverse/libcloud,jimbobhickville/libcloud,wrigri/libcloud,StackPointCloud/libcloud,pquentin/libcloud,StackPointCloud/libcloud,apache/libcloud,watermelo/libcloud,StackPointCloud/libcloud,andrewsomething/libcloud,SecurityCompass/libcloud,samuelchong/libcloud,DimensionDataCBUSydney/libcloud,wuyuewen/libcloud,curoverse/libcloud,erjohnso/libcloud,samuelchong/libcloud,iPlantCollaborativeOpenSource/libcloud,ZuluPro/libcloud,erjohnso/libcloud,apache/libcloud,mathspace/libcloud,wrigri/libcloud,techhat/libcloud,andrewsomething/libcloud,cryptickp/libcloud,jimbobhickville/libcloud,Scalr/libcloud,DimensionDataCBUSydney/libcloud,lochiiconnectivity/libcloud,t-tran/libcloud,supertom/libcloud,wido/libcloud,supertom/libcloud,SecurityCompass/libcloud,illfelder/libcloud,wuyuewen/libcloud,mathspace/libcloud,apache/libcloud,ZuluPro/libcloud,cryptickp/libcloud,DimensionDataCBUSydney/libcloud,wido/libcloud,lochiiconnectivity/libcloud,mgogoulos/libcloud,cryptickp/libcloud,andrewsomething/libcloud,Scalr/libcloud,mistio/libcloud,erjohnso/libcloud,jimbobhickville/libcloud,Scalr/libcloud,iPlantCollaborativeOpenSource/libcloud,Kami/libcloud,t-tran/libcloud,lochiiconnectivity/libcloud,NexusIS/libcloud,samuelchong/libcloud,mistio/libcloud,Kami/libcloud,mistio/libcloud,niteoweb/libcloud,ByteInternet/libcloud,techhat/libcloud,watermelo/libcloud,Kami/libcloud,illfelder/libcloud,ByteInternet/libcloud,pquentin/libcloud,mgogoulos/libcloud,wuyuewen/libcloud,ByteInternet/libcloud,niteoweb/libcloud,mgogoulos/libcloud,t-tran/libcloud,niteoweb/libcloud,vongazman/libcloud,wido/libcloud,iPlantCollaborativeOpenSource/libcloud,SecurityCompass/libcloud,NexusIS/libcloud,illfelder/libcloud