pnfs: fix for write length returned

fixes an issue introduced by commit 1f7e560a9a, "pnfs: fix for short write on ds error"

when a write is satisfied completely by pnfs, the upcall was returning out_len=0.  the only time i noticed this was against python server, where cp in cygwin would succeed but print 'No space left on device'

Signed-off-by: Casey Bodley <cbodley@citi.umich.edu>

daemon/readwrite.c

@@ -296,9 +296,8 @@ static int handle_write(nfs41_upcall *upcall)
 #endif
 
     status = write_to_mds(upcall, &stateid);
-
-    args->out_len += pnfs_bytes_written;
 out:
+    args->out_len += pnfs_bytes_written;
     return status;
 }