detect: fix scan-build warnings

detect: fix scan-build warnings

detect-engine-address.c:1140:17: warning: Use of memory after it is freed [unix.Malloc]
            r = DetectAddressCmp(ag, ag2);
                ^~~~~~~~~~~~~~~~~~~~~~~~~
detect-engine-address.c:1169:17: warning: Use of memory after it is freed [unix.Malloc]
            r = DetectAddressCmp(ag, ag2);
                ^~~~~~~~~~~~~~~~~~~~~~~~~
2 warnings generated.

detect-engine-port.c:1161:9: warning: Use of memory after it is freed [unix.Malloc]
        DetectPortPrint(ag2);
        ^~~~~~~~~~~~~~~~~~~~
1 warning generated.

Bug: #3150.
Bug: #3151.