Fix ssh-agent shutdown on terminal close

With Python 3.2 the default value for close_fds changed from True to
False. Therefore ssh-agent inherits the file descriptors to /dev/tty
from ssh-ident. At least on Cygwin this causes ssh-agent to shut down
when the terminal is closed.

Signed-off-by: Konrad Gräfe <[email protected]>

Author: kgraefe

ssh-ident

@@ -796,7 +796,9 @@ class AgentManager(object):
     print("Preparing new agent for identity {0}".format(identity), file=sys.stderr,
         loglevel=LOG_DEBUG)
     retval = subprocess.call(
-        ["/usr/bin/env", "-i", "/bin/sh", "-c", "ssh-agent > {0}".format(agentfile)])
+        ["/usr/bin/env", "-i", "/bin/sh", "-c", "ssh-agent > {0}".format(agentfile)],
+        close_fds=True
+    )
     return agentfile
 
   @staticmethod