[PATCH] erofs-utils: fix resource leaks and missing returns on error paths

[Nithurshen]

Hi Xiang,

Thanks for the suggestion.

I have started working on formalizing the truncated image
scenario into a test case for experimental-tests. I'll 
implement it so that we can automate the image corruption
and verify the FUSE daemon's error-handling behavior in
future.

Since there is already a test-case I sent with code 028,
is it okay if I send this one with 029?

I will send the patch for the test case shortly.

Thanks and Regards,
Nithurshen