remove arbitrary 5 second timeout for shelling out

This seems to just make the server unstable under load, and most commands made
a point to remove the timeout. If there's a particular command that's risky
and may lock up, it should be given a timeout, not all of them.
Merge pull request #34 from cloudfoundry/no-timeout

remove arbitrary 5 second timeout for shelling out
Auto-merge remote-tracking branch 'upstream/master'