detect: remove unneeded size in DetectEngineCtx

sig_array_size can easily be calculated with length and is only used at
one place for debugging purposes. Remove it from the DetectEngineCtx
struct to avoid making it unnecessarily heavy.

src/detect-engine-build.c

@@ -1361,14 +1361,10 @@ int SigPrepareStage1(DetectEngineCtx *de_ctx)
     }
 
     de_ctx->sig_array_len = DetectEngineGetMaxSigId(de_ctx);
-    de_ctx->sig_array_size = (de_ctx->sig_array_len * sizeof(Signature *));
     de_ctx->sig_array = (Signature **)SCCalloc(de_ctx->sig_array_len, sizeof(Signature *));
     if (de_ctx->sig_array == NULL)
         goto error;
 
-    SCLogDebug("signature lookup array: %" PRIu32 " sigs, %" PRIu32 " bytes",
-               de_ctx->sig_array_len, de_ctx->sig_array_size);
-
     /* now for every rule add the source group */
     for (Signature *s = de_ctx->sig_list; s != NULL; s = s->next) {
         de_ctx->sig_array[s->num] = s;

src/detect.h

@@ -850,7 +850,6 @@ typedef struct DetectEngineCtx_ {
     SRepCIDRTree *srepCIDR_ctx;
 
     Signature **sig_array;
-    uint32_t sig_array_size; /* size in bytes */
     uint32_t sig_array_len;  /* size in array members */
 
     uint32_t signum;