Fix memory leak in sssdpac_verify()
Resolves https://fedorahosted.org/sssd/ticket/2803
Reviewed-by: Sumit Bose <sbose@redhat.com>
(cherry picked from commit b4c44ebb8997d3debb33607c123ccfd9926e0cba)
(cherry picked from commit c542366e4ddb2984107de1af2363adb184653290)