MB-11356: [cbcollect_info] don't pass our stdin to our childs

Which causes Popen to hang on windows. And also because our childs
don't really need our stdin.

Change-Id: I2214fcfe848afc0c3454eed6382323b991e8f67a
Reviewed-on: http://review.couchbase.org/38057
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>