Fix struct FILE * leak on error (in disabled by default hesiod support code).

Submitted by:	henning petersen <henning.petersen t-online de>
PR:	153756
MFC after:	1 week

lib/libc/net/hesiod.c

@@ -324,6 +324,7 @@ read_config_file(ctx, filename)
 			    ? &ctx->lhs : &ctx->rhs;
 			*which = strdup(data);
 			if (!*which) {
+				fclose(fp);
 				errno = ENOMEM;
 				return -1;
 			}