Initialize printed buffer

- var_decl: Declaring variable "tbuf" without initializer
- assign: Assigning: "target.base" = "tbuf", which points to
  uninitialized data
- assign: Assigning: "r.base" = "target.base", which points to
  uninitialized data

I expect it would correctly initialize length always. Add simple
initialization to silent coverity.

bin/dig/host.c

@@ -211,15 +211,9 @@ printsection(dns_message_t *msg, dns_section_t sectionid,
 	isc_result_t result, loopresult;
 	isc_region_t r;
 	dns_name_t empty_name;
-	char tbuf[4096];
+	char tbuf[4096] = { 0 };
 	bool first;
-	bool no_rdata;
-
-	if (sectionid == DNS_SECTION_QUESTION) {
-		no_rdata = true;
-	} else {
-		no_rdata = false;
-	}
+	bool no_rdata = (sectionid == DNS_SECTION_QUESTION);
 
 	if (headers) {
 		printf(";; %s SECTION:\n", section_name);