Fix bug with logical signature Intermediates feature

The file type check for the logical signature Intermediates feature is
off-by-one and so the first layer checked is supposed to be the first
parent of the current layer, but is in fact the current layer.

This commit fixes the issue by correctly checking starting at -2 instead
of -1. (-1 is the current layer, 0 is the outermost layer).

libclamav/matcher.c

@@ -791,7 +791,9 @@ cl_error_t cli_scan_desc(int desc, cli_ctx *ctx, cli_file_t ftype, uint8_t ftonl
 static int intermediates_eval(cli_ctx *ctx, struct cli_ac_lsig *ac_lsig)
 {
     uint32_t i, icnt = ac_lsig->tdb.intermediates[0];
-    int32_t j = -1;
+
+    // -1 is the deepest layer (the current layer), so we start at -2, which is the first ancestor
+    int32_t j = -2;
 
     if (ctx->recursion_level < icnt)
         return 0;