fabric/fabric — pull request #493 by rspeer (2011-12-05 21:06:42+00:00)
Title: Avoid "Resource temporarily unavailable" crashes in parallel mode

I've found that I get crashes sometimes with "Resource temporarily unavailable" in parallel mode.

This particularly happens if one of the machines happens to prompt for a password. Of course that's something to be avoided, but it should also be recoverable. If I type the password, the process will continue as normal for a while, but then later it will crash with an IOError, "Resource temporarily unavailable".

I think the reason might be that the password code is setting `chan.input_enabled` to True when it is done, regardless of whether it was True before. If that's what's going on, this should fix the problem.