Add unreachable code

Coverity thinks it can do the default case.

src/syncterm/ripper.c

@@ -14932,6 +14932,8 @@ do_rip_command(int level, int sublevel, int cmd, const char *rawargs)
 									case 7:
 										zmodem_upload(rip.bbs, fp, cache_path);
 										break;
+									default: // Can't happen, thanks Coverity
+										fclose(fp);
 								}
 								suspend_rip(false);
 								free(uldir);