findClosest() didn't handle the root zone correctly

git-svn-id: svn://bind10.isc.org/svn/bind10/trunk@1222 e5f2f494-b856-4b98-b285-d166d9295462

src/lib/auth/data_source_sqlite3.cc

@@ -298,7 +298,7 @@ Sqlite3DataSrc::findClosest(const char* const name,
         while (*current != '.' && *current != 0) {
             ++current;
         }
-        if (*current == '.') {
+        if (*current == '.' && *(current + 1) != '\0') {
             ++current;
         }
     }