tests: Fix a memory leak in test_goal_get_solution()
tests: Fix a memory leak in test_goal_get_solution()

Closes: #232
Approved by: cgwalters

rpm-software-management/libhif,rpm-software-management/libdnf,rpm-software-management/libhif,edynox/libdnf,rpm-software-management/libhif,edynox/libdnf,rpm-software-management/libdnf,edynox/libdnf,rpm-software-management/libdnf,hughsie/libhif,hughsie/libhif,hughsie/libhif,rpm-software-management/libhif,Conan-Kudo/libhif,Conan-Kudo/libhif,rpm-software-management/libdnf,edynox/libdnf,Conan-Kudo/libhif,hughsie/libhif,Conan-Kudo/libhif