cbcollect_info generates corrupted file if not run with permissions to read certain directories

When running cbcollect_info as a user that does not have permission to read /opt/couchbase/var/lib (might be other restrictions as well), the tool will run but create a corrupted log file.

Please enhance the tool to check for the necessary permissions before hand (usually recommending to run as root) so that the customer does not have to accidentally create and upload a corrupted log file.