Fixed Windows build regarding FsTest.Xattr.
Fixed Windows build regarding FsTest.Xattr.

The xattr utilities in stout are only defined on Linux and OSX
thus far.  The associated test needs to be #ifdef'd appropriately.

verizonlabs/mesos,verizonlabs/mesos,abudnik/mesos,kaysoky/mesos,asamerh4/mesos,zmalik/mesos,yuquanshan/customizedMesos,jpeach/mesos,chhsia0/mesos,zmalik/mesos,yuquanshan/customizedMesos,asamerh4/mesos,dforsyth/mesos,reneploetz/mesos,Gilbert88/mesos,dforsyth/mesos,kaysoky/mesos,zmalik/mesos,chhsia0/mesos,reneploetz/mesos,neilconway/mesos,Gilbert88/mesos,kaysoky/mesos,zmalik/mesos,yuquanshan/customizedMesos,Aman-Jain-14/customizedMesos,andschwa/mesos,abudnik/mesos,yuquanshan/customizedMesos,kaysoky/mesos,chhsia0/mesos,neilconway/mesos,asamerh4/mesos,chhsia0/mesos,asamerh4/mesos,Aman-Jain-14/customizedMesos,jpeach/mesos,Aman-Jain-14/customizedMesos,zmalik/mesos,gsantovena/mesos,yuquanshan/customizedMesos,andschwa/mesos,verizonlabs/mesos,asamerh4/mesos,andschwa/mesos,neilconway/mesos,asamerh4/mesos,jpeach/mesos,craimbert/mesos,gsantovena/mesos,Gilbert88/mesos,andschwa/mesos,jpeach/mesos,dforsyth/mesos,reneploetz/mesos,kaysoky/mesos,chhsia0/mesos,abudnik/mesos,Aman-Jain-14/customizedMesos,jpeach/mesos,craimbert/mesos,dforsyth/mesos,gsantovena/mesos,kaysoky/mesos,dforsyth/mesos,Aman-Jain-14/customizedMesos,reneploetz/mesos,asamerh4/mesos,Aman-Jain-14/customizedMesos,andschwa/mesos,craimbert/mesos,jpeach/mesos,yuquanshan/customizedMesos,verizonlabs/mesos,Gilbert88/mesos,reneploetz/mesos,andschwa/mesos,abudnik/mesos,verizonlabs/mesos,reneploetz/mesos,dforsyth/mesos,Gilbert88/mesos,gsantovena/mesos,kaysoky/mesos,gsantovena/mesos,reneploetz/mesos,verizonlabs/mesos,gsantovena/mesos,craimbert/mesos,zmalik/mesos,gsantovena/mesos,zmalik/mesos,abudnik/mesos,chhsia0/mesos,Gilbert88/mesos,Aman-Jain-14/customizedMesos,neilconway/mesos,craimbert/mesos,dforsyth/mesos,neilconway/mesos,neilconway/mesos,verizonlabs/mesos,abudnik/mesos,neilconway/mesos,andschwa/mesos,yuquanshan/customizedMesos,craimbert/mesos,Gilbert88/mesos,jpeach/mesos,abudnik/mesos,craimbert/mesos,chhsia0/mesos