memory leak on agent test

[EddyTheCo]

./build/default-develop/tests/gconnman_agent_test_valgrind

[  PASSED  ] 0 tests.
[  SKIPPED ] 1 test, listed below:
[  SKIPPED ] ConnmanAgent.ReportErrorRequestsRetry
[  FAILED  ] 2 tests, listed below:
[  FAILED  ] ConnmanAgent.ReportErrorIsAnswered
[  FAILED  ] ConnmanAgent.CancelIsAnswered

 2 FAILED TESTS
==80888== 
==80888== HEAP SUMMARY:
==80888==     in use at exit: 131,016 bytes in 1,510 blocks
==80888==   total heap usage: 45,084 allocs, 43,574 frees, 1,991,813 bytes allocated
==80888== 
==80888== LEAK SUMMARY:
==80888==    definitely lost: 32 bytes in 2 blocks
==80888==    indirectly lost: 967 bytes in 2 blocks
==80888==      possibly lost: 960 bytes in 3 blocks
==80888==    still reachable: 115,217 bytes in 1,375 blocks
==80888==         suppressed: 0 bytes in 0 blocks
==80888== Reachable blocks (those to which a pointer was found) are not shown.
==80888== To see them, rerun with: --leak-check=full --show-leak-kinds=all
==80888== 
==80888== For lists of detected and suppressed errors, rerun with: -s
==80888== ERROR SUMMARY: 4 errors from 4 contexts (suppressed: 0 from 0)