Re-enable the SFTP nosetests. Seems like the latest version of paramiko no

longer has the problems we were encountering before. Also required a quick
fix to SFTPFS.removeddir(..., recursive=True) 

fs/sftpfs.py

@@ -545,7 +545,8 @@ class SFTPFS(FS):
             raise
         if recursive:
             try:
-                self.removedir(dirname(path),recursive=True)
+                if dirname(path) not in ('', '/'):
+                    self.removedir(dirname(path),recursive=True)
             except DirectoryNotEmptyError:
                 pass
 

fs/tests/test_expose.py

@@ -127,7 +127,6 @@ except ImportError:
 class TestSFTPFS(TestRPCFS):
     
     __test__ = not PY3
-    __test__ = False
 
     def makeServer(self,fs,addr):
         return BaseSFTPServer(addr,fs)