[cbcollect_info] log python version in verbose mode

Change-Id: I7dee12b7453d4751a95608ccf80fb58d0d6a1584
Reviewed-on: http://review.couchbase.org/38056
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>