Revert stamps even if vim failed

bin/vim-bx

@@ -31,7 +31,7 @@ my $real_vim = `/usr/bin/env -i which vim`;
 chomp $real_vim;
 my $cmd = join ' ', $real_vim, @ARGV;
 system($cmd) == 0
-    or die "vim failed: $!";
+    or warn "vim failed: $!";
 
 # restore stamps if they have changed
 foreach (keys %$original_stamp) {