output the same conversion code regardless of the build environment

[masa213f]

What

When I run make generate inside GOPATH, it generates a different code than the committed code.

$ mkdir -p $GOPATH/src/github.com/cybozu-go/
$ cd $GOPATH/src/github.com/cybozu-go/
$ git clone git@github.com:cybozu-go/moco.git
$ cd moco
$ make setup
$ make generate

Then conversion-gen outputs the following error:

/home/m001282/go/src/github.com/cybozu-go/moco/bin/conversion-gen -i ./api/v1beta1/ -o . -O zz_generated.conversion --go-header-file hack/boilerplate.go.txt
E0425 06:42:46.657636  931029 conversion.go:193] Rename function github.com/cybozu-go/moco/api/v1beta1 Convert__MySQLClusterSpec_To_v1beta2_MySQLClusterSpec -> Convert_v1beta1_MySQLClusterSpec_To_v1beta2_MySQLClusterSpec to match expected conversion signature
E0425 06:42:46.657779  931029 conversion.go:193] Rename function github.com/cybozu-go/moco/api/v1beta1 Convert__MySQLCluster_To_v1beta2_MySQLCluster -> Convert_v1beta1_MySQLCluster_To_v1beta2_MySQLCluster to match expected conversion signature
E0425 06:42:46.657885  931029 conversion.go:193] Rename function github.com/cybozu-go/moco/api/v1beta1 Convert_v1beta2_MySQLClusterSpec_To__MySQLClusterSpec -> Convert_v1beta2_MySQLClusterSpec_To_v1beta1_MySQLClusterSpec to match expected conversion signature
E0425 06:42:46.657960  931029 conversion.go:193] Rename function github.com/cybozu-go/moco/api/v1beta1 Convert_v1beta2_MySQLCluster_To__MySQLCluster -> Convert_v1beta2_MySQLCluster_To_v1beta1_MySQLCluster to match expected conversion signature
E0425 06:42:46.658043  931029 conversion.go:193] Rename function github.com/cybozu-go/moco/api/v1beta1 Convert_v1beta2_PodTemplateSpec_To__PodTemplateSpec -> Convert_v1beta2_PodTemplateSpec_To_v1beta1_PodTemplateSpec to match expected conversion signature
E0425 06:42:46.681872  931029 conversion.go:755] Warning: could not find nor generate a final Conversion function for github.com/cybozu-go/moco/api/v1beta1.MySQLClusterSpec -> github.com/cybozu-go/moco/api/v1beta2.MySQLClusterSpec
E0425 06:42:46.682112  931029 conversion.go:756]   the following fields need manual conversion:
E0425 06:42:46.682131  931029 conversion.go:758]       - ServiceTemplate
E0425 06:42:46.683002  931029 conversion.go:755] Warning: could not find nor generate a final Conversion function for github.com/cybozu-go/moco/api/v1beta2.MySQLClusterSpec -> github.com/cybozu-go/moco/api/v1beta1.MySQLClusterSpec
E0425 06:42:46.683028  931029 conversion.go:756]   the following fields need manual conversion:
E0425 06:42:46.683036  931029 conversion.go:758]       - PrimaryServiceTemplate
E0425 06:42:46.683043  931029 conversion.go:758]       - ReplicaServiceTemplate
E0425 06:42:46.692662  931029 conversion.go:755] Warning: could not find nor generate a final Conversion function for github.com/cybozu-go/moco/api/v1beta2.PodTemplateSpec -> github.com/cybozu-go/moco/api/v1beta1.PodTemplateSpec
E0425 06:42:46.692717  931029 conversion.go:756]   the following fields need manual conversion:
E0425 06:42:46.692756  931029 conversion.go:758]       - OverwriteContainers

And It craetes a file in the unexpedted path: <workdir>/github.com/cybozu-go/moco/api/v1beta1/zz_generated.conversion.go

How

The following issue may be helpful.
kubernetes-sigs/cluster-api#4349

Checklist

• Finish implementation of the issue
• Test all functions
• Have enough logs to trace activities
• Notify developers of necessary actions