SSH: fix download/upload with -1 exit status

Author: kilimnik

pwnlib/tubes/ssh.py

@@ -1363,7 +1363,7 @@ def update(has, total):
             update(len(data), total)
 
         result = c.wait()
-        if result != 0:
+        if result != 0 or result != -1:
             h.failure('Could not download file %r (%r)' % (remote, result))
             return
 
@@ -1543,7 +1543,7 @@ def upload_data(self, data, remote):
             s.shutdown('send')
             data   = s.recvall()
             result = s.wait()
-            if result != 0:
+            if result != 0 or result != -1:
                 self.error("Could not upload file %r (%r)\n%s" % (remote, result, data))
 
     def upload_file(self, filename, remote = None):