Improve memory cleanup for decoder-events

To address:

~~Dr.M~~ Error #1: LEAK 1 direct bytes 0x0892c108-0x0892c109 + 0 indirect bytes
~~Dr.M~~ # 0 replace_malloc                        [/work/drmemory_package/common/alloc_replace.c:2292]
~~Dr.M~~ # 1 DetectEngineEventParse                [/home/victor/dev/oisf/src/detect-engine-event.c:173]
~~Dr.M~~ # 2 _DetectEngineEventSetup               [/home/victor/dev/oisf/src/detect-engine-event.c:204]
~~Dr.M~~ # 3 DetectDecodeEventSetup                [/home/victor/dev/oisf/src/detect-engine-event.c:248]
~~Dr.M~~ # 4 SigParseOptions                       [/home/victor/dev/oisf/src/detect-parse.c:510]
~~Dr.M~~ # 5 SigParseOptions                       [/home/victor/dev/oisf/src/detect-parse.c:523]
~~Dr.M~~ # 6 SigParse                              [/home/victor/dev/oisf/src/detect-parse.c:881]
~~Dr.M~~ # 7 SigInitHelper                         [/home/victor/dev/oisf/src/detect-parse.c:1309]
~~Dr.M~~ # 8 SigInit                               [/home/victor/dev/oisf/src/detect-parse.c:1456]
~~Dr.M~~ # 9 DetectEngineAppendSig                 [/home/victor/dev/oisf/src/detect-parse.c:1728]
~~Dr.M~~ #10 DetectLoadSigFile                     [/home/victor/dev/oisf/src/detect.c:334]
~~Dr.M~~ #11 SigLoadSignatures                     [/home/victor/dev/oisf/src/detect.c:422]
ipproto: improve cleanup

To address:
~~Dr.M~~ Error #2: LEAK 16 direct bytes 0x08399688-0x08399698 + 2 indirect bytes
~~Dr.M~~ # 0 replace_malloc                      [/work/drmemory_package/common/alloc_replace.c:2292]
~~Dr.M~~ # 1 SigMatchAlloc                       [/home/victor/dev/oisf/src/detect-parse.c:201]
~~Dr.M~~ # 2 DetectIPProtoSetup                  [/home/victor/dev/oisf/src/detect-ipproto.c:523]
~~Dr.M~~ # 3 SigParseOptions                     [/home/victor/dev/oisf/src/detect-parse.c:510]
~~Dr.M~~ # 4 SigParseOptions                     [/home/victor/dev/oisf/src/detect-parse.c:523]
~~Dr.M~~ # 5 SigParse                            [/home/victor/dev/oisf/src/detect-parse.c:881]
~~Dr.M~~ # 6 SigInitHelper                       [/home/victor/dev/oisf/src/detect-parse.c:1309]
~~Dr.M~~ # 7 SigInit                             [/home/victor/dev/oisf/src/detect-parse.c:1456]
~~Dr.M~~ # 8 DetectEngineAppendSig               [/home/victor/dev/oisf/src/detect-parse.c:1728]
~~Dr.M~~ # 9 DetectLoadSigFile                   [/home/victor/dev/oisf/src/detect.c:334]
~~Dr.M~~ #10 SigLoadSignatures                   [/home/victor/dev/oisf/src/detect.c:422]
~~Dr.M~~ #11 LoadSignatures                      [/home/victor/dev/oisf/src/suricata.c:1706]
Properly clean up decoder event rules

Addresses:
~~Dr.M~~ Error #3: LEAK 120 direct bytes 0x08a26ac8-0x08a26b40 + 1871 indirect bytes
~~Dr.M~~ # 0 replace_malloc                               [/work/drmemory_package/common/alloc_replace.c:2292]
~~Dr.M~~ # 1 SigGroupHeadAlloc                            [/home/victor/dev/oisf/src/detect-engine-siggroup.c:144]
~~Dr.M~~ # 2 SigGroupHeadAppendSig                        [/home/victor/dev/oisf/src/detect-engine-siggroup.c:1014]
~~Dr.M~~ # 3 DetectEngineAddDecoderEventSig               [/home/victor/dev/oisf/src/detect.c:3026]
~~Dr.M~~ # 4 SigAddressPrepareStage2                      [/home/victor/dev/oisf/src/detect.c:3075]
~~Dr.M~~ # 5 SigGroupBuild                                [/home/victor/dev/oisf/src/detect.c:4311]
~~Dr.M~~ # 6 SigLoadSignatures                            [/home/victor/dev/oisf/src/detect.c:464]
~~Dr.M~~ # 7 LoadSignatures                               [/home/victor/dev/oisf/src/suricata.c:1706]
~~Dr.M~~ # 8 main                                         [/home/victor/dev/oisf/src/suricata.c:1994]