Fix wrong original git service type on a migrated repository

[lunny]

The original git service type should be 2 but now it's 0. This PR will fix that.

[codecov-io]

Codecov Report

Merging #9693 into master will increase coverage by <.01%.
The diff coverage is 78.26%.

@@            Coverage Diff             @@
##           master    #9693      +/-   ##
==========================================
+ Coverage   42.25%   42.25%   +<.01%     
==========================================
  Files         589      590       +1     
  Lines       77989    78002      +13     
==========================================
+ Hits        32954    32960       +6     
- Misses      40994    41001       +7     
  Partials     4041     4041

Impacted Files	Coverage Δ
models/migrations/migrations.go	1.3% <ø> (ø)	⬆️
models/migrations/v119.go	0% <0%> (ø)
modules/migrations/gitea.go	7.96% <0%> (-0.02%)	⬇️
routers/repo/repo.go	30.23% <100%> (+1.01%)	⬆️
models/repo.go	47.9% <100%> (+0.02%)	⬆️
models/task.go	24.65% <100%> (+0.51%)	⬆️
routers/api/v1/repo/repo.go	69.59% <100%> (+0.03%)	⬆️
services/pull/temp_repo.go	31.62% <0%> (-2.57%)	⬇️
services/pull/merge.go	53.14% <0%> (-0.79%)	⬇️
... and 1 more

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