avformat/mov: Corner case encryption error cleanup in mov_read_senc()

Fixes: memleak
Fixes: 42341/clusterfuzz-testcase-minimized-ffmpeg_dem_MOV_fuzzer-4566632823914496

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit 8ee0e4abcb)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavformat/mov.c

@@ -6140,6 +6140,8 @@ static int mov_read_senc(MOVContext *c, AVIOContext *pb, MOVAtom atom)
         }
         if (pb->eof_reached) {
             av_log(c->fc, AV_LOG_ERROR, "Hit EOF while reading senc\n");
+            if (ret >= 0)
+                av_encryption_info_free(encryption_index->encrypted_samples[i]);
             ret = AVERROR_INVALIDDATA;
         }