[stunnel-users] fix resource leaks and potential null

[Arthur Mesh]

On Tue, Feb 05, 2013 at 12:57:47PM -0500, Brian Wilkins wrote:
> No matter..this is the right way to check if a pointer is null in C.
> http://stackoverflow.com/questions/7970617/how-can-i-check-if-char-variable-points-to-empty-string

Yes, but you can't check for a value of an uninitialized variable.