[v9_11] fix dyndb issues; isc_errno_toresult()

4445.	[cleanup]	isc_errno_toresult() can now be used to call the
			formerly private function isc__errno2result().
			[RT #43050]

4444.	[bug]		Fixed some issues related to dyndb: A bug caused
			braces to be omitted when passing configuration text
			from named.conf to a dyndb driver, and there was a
			use-after-free in the sample dyndb driver. [RT #43050]

Patch for dyndb driver submitted by Petr Spacek at Red Hat.

(cherry picked from commit 3390d74e33)

bin/tests/system/checkconf/good.conf

@@ -145,3 +145,12 @@ key "mykey" {
 	algorithm "hmac-md5";
 	secret "qwertyuiopasdfgh";
 };
+dyndb "name" "library.so" {
+        this;
+        \};
+        is a {
+                "test" { \{ of; the; };
+        } bracketed;
+        "text \"";
+        system;
+};