Fix error when calculating tarball size of manifest

[tydra-wang]

Manifest is marshalled repeatedly.

[codecov-io]

Codecov Report

Merging #804 into master will increase coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #804      +/-   ##
==========================================
+ Coverage   74.88%   74.91%   +0.02%     
==========================================
  Files         103      103              
  Lines        4312     4309       -3     
==========================================
- Hits         3229     3228       -1     
+ Misses        606      605       -1     
+ Partials      477      476       -1     

Impacted Files	Coverage Δ
pkg/v1/tarball/write.go	62.42% <ø> (+0.49%)	⬆️

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[jonjohnsonjr]

cc @deitch can you take a look?

[deitch]

It makes sense to me. I cannot understand how it worked before, unless I simply don't understand it now.

[jonjohnsonjr]

Thanks!

[tydra-wang]

It makes sense to me. I cannot understand how it worked before, unless I simply don't understand it now.

The size is only used to calculate the progress.
And the tarball padding makes error happens occasionally.