pure: use /proc/self/fd to implement countOpenFileDescriptors
pure: use /proc/self/fd to implement countOpenFileDescriptors

Python's poll.poll() seems to fail outright if fed an invalid file
descriptor, as opposed to the libc behavior which flags individual
descriptors as invalid. This way is probably faster anyway.

fedora-conary/conary,fedora-conary/conary,fedora-conary/conary,fedora-conary/conary,fedora-conary/conary