bug #1754: change default attach prefix to file (compatible with xen 3 and 4)
bug #1754: change default attach prefix to file (compatible with xen 3 and 4)

hsanjuan/one,OpenNebula/one,unistra/one,tuxmea/one,hsanjuan/one,atodorov-storpool/one,Terradue/one,ggalancs/one,juanmont/one,mattthias/one,juanmont/one,spirit03/one,alvarosimon/one,Terradue/one,cloudweavers/one,baby-gnu/one,ohamada/one,dberzano/opennebula-torino,mattthias/one,OpenNebula/one,ggalancs/one,mattthias/one,baby-gnu/one,abelCoronado93/one,OpenNebula/one,Terradue/one,hsanjuan/one,unistra/one,atodorov-storpool/one,dberzano/opennebula-torino,hsanjuan/one,alvarosimon/one,dberzano/opennebula-torino,unistra/one,abelCoronado93/one,unistra/one,alvarosimon/one,goberle/one,tuxmea/one,alvarosimon/one,spirit03/one,dberzano/opennebula-torino,hsanjuan/one,ohamada/one,atodorov-storpool/one,mattthias/one,OpenNebula/one,tuxmea/one,OpenNebula/one,Terradue/one,baby-gnu/one,alvarosimon/one,alvarosimon/one,baby-gnu/one,ohamada/one,OpenNebula/one,spirit03/one,abelCoronado93/one,baby-gnu/one,fasrc/one,goberle/one,ohamada/one,spirit03/one,atodorov-storpool/one,dberzano/opennebula-torino,cloudweavers/one,atodorov-storpool/one,juanmont/one,mattthias/one,abelCoronado93/one,abelCoronado93/one,tuxmea/one,hsanjuan/one,atodorov-storpool/one,Terradue/one,fasrc/one,mattthias/one,baby-gnu/one,abelCoronado93/one,ggalancs/one,baby-gnu/one,cloudweavers/one,ohamada/one,ohamada/one,ggalancs/one,spirit03/one,Terradue/one,fasrc/one,juanmont/one,ggalancs/one,dberzano/opennebula-torino,Terradue/one,spirit03/one,ohamada/one,abelCoronado93/one,fasrc/one,unistra/one,juanmont/one,cloudweavers/one,cloudweavers/one,spirit03/one,hsanjuan/one,cloudweavers/one,OpenNebula/one,unistra/one,spirit03/one,juanmont/one,cloudweavers/one,tuxmea/one,ggalancs/one,juanmont/one,atodorov-storpool/one,fasrc/one,goberle/one,fasrc/one,ggalancs/one,goberle/one,ohamada/one,fasrc/one,Terradue/one,baby-gnu/one,mattthias/one,OpenNebula/one,unistra/one,goberle/one,mattthias/one,alvarosimon/one,atodorov-storpool/one,goberle/one,unistra/one,atodorov-storpool/one,abelCoronado93/one,goberle/one,tuxmea/one,ggalancs/one,OpenNebula/one,hsanjuan/one,tuxmea/one,juanmont/one,goberle/one,tuxmea/one,fasrc/one,cloudweavers/one,alvarosimon/one,juanmont/one,dberzano/opennebula-torino