Bugfix: patch can't overwrite twice

[lucklove]

Fix #556

Signed-off-by: lucklove gnu.crazier@gmail.com

[CLAassistant]

All committers have signed the CLA.

[codecov-commenter]

Codecov Report

Merging #558 into master will increase coverage by 10.41%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           master     #558       +/-   ##
===========================================
+ Coverage   39.84%   50.26%   +10.41%     
===========================================
  Files         201      219       +18     
  Lines       14847    15877     +1030     
===========================================
+ Hits         5916     7980     +2064     
+ Misses       8072     6765     -1307     
- Partials      859     1132      +273     

Flag	Coverage Δ
#coverage	50.26% <ø> (+10.41%)	⬆️

Impacted Files	Coverage Δ
...o/src/github.com/pingcap/tiup/server/store/sync.go	28.57% <0.00%> (-28.58%)	⬇️
....com/pingcap/tiup/pkg/cluster/clusterutil/retry.go	50.00% <0.00%> (-17.50%)	⬇️
go/src/github.com/pingcap/tiup/cmd/mirror.go	39.95% <0.00%> (-6.89%)	⬇️
...ingcap/tiup/components/playground/instance/tidb.go	85.36% <0.00%> (-5.34%)	⬇️
...ingcap/tiup/components/playground/instance/tikv.go	75.00% <0.00%> (-4.32%)	⬇️
go/src/github.com/pingcap/tiup/cmd/root.go	60.43% <0.00%> (-3.85%)	⬇️
...pingcap/tiup/components/cluster/command/destroy.go	60.37% <0.00%> (-2.79%)	⬇️
...cap/tiup/components/playground/instance/tiflash.go	61.29% <0.00%> (-2.49%)	⬇️
...om/pingcap/tiup/components/cluster/command/root.go	43.03% <0.00%> (-2.24%)	⬇️
...om/pingcap/tiup/components/cluster/command/test.go	62.22% <0.00%> (-2.07%)	⬇️
... and 120 more

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[ti-srebot]

@july2993,Thanks for your review.

[ti-srebot]

LGTM

[ti-srebot]

@lonng,Thanks for your review.