fixed a goroutine leak

[ktarplee]

If the rc is not closed (which happens when the files with the same digest already exists, due to the same image being added to the OCI layout directory twice) then

if s, err := os.Stat(file); err == nil && !s.IsDir() && (s.Size() == size || size == -1) {
	return nil
}

will not close the io.ReadCloser leaking a goroutine here

[codecov-commenter]

Codecov Report

Merging #1705 (009eea0) into main (a927d7c) will increase coverage by 0.10%.
The diff coverage is 33.33%.

@@            Coverage Diff             @@
##             main    #1705      +/-   ##
==========================================
+ Coverage   72.09%   72.20%   +0.10%     
==========================================
  Files         121      121              
  Lines        9733     9720      -13     
==========================================
+ Hits         7017     7018       +1     
+ Misses       2039     2028      -11     
+ Partials      677      674       -3     

Impacted Files	Coverage Δ
pkg/crane/get.go	92.59% <0.00%> (-7.41%)	⬇️
pkg/v1/remote/fetcher.go	74.50% <ø> (+1.78%)	⬆️
pkg/v1/remote/puller.go	72.30% <ø> (+2.80%)	⬆️
pkg/v1/layout/write.go	48.26% <100.00%> (+0.18%)	⬆️

... and 1 file with indirect coverage changes

[ktarplee]

Closes #1706

[imjasonh]

Nice!