Fix possible NULL dereference
Fix possible NULL dereference

Addressing:

openscap-1.3.5/src/XCCDF/xccdf_session.c:1349:15: warning[-Wanalyzer-possible-null-dereference]: dereference of possibly-NULL 'to'

OpenSCAP/openscap,OpenSCAP/openscap,OpenSCAP/openscap,OpenSCAP/openscap,OpenSCAP/openscap,OpenSCAP/openscap