crit/images: fix name conflict with letsencrypt

The core.proto and so.proto files provided by criu have conflicting
names with the proto files included in

https://github.com/letsencrypt/boulder

Since protobuf v1.26.0 a hard error is reported when a compiled Go
program starts up that has multiple conflicting protobuf names
linked into it. This results in the following error when running
the podman tests:

panic: proto: file "sa.proto" is already registered
	previously from: "github.com/letsencrypt/boulder/sa/proto"
	currently from:  "github.com/checkpoint-restore/go-criu/v6/crit/images"
See https://developers.google.com/protocol-buffers/docs/reference/go/faq#namespace-conflict

goroutine 1 [running]:
google.golang.org/protobuf/reflect/protoregistry.glob..func1({0x1b0b380?, 0xc0004ce240?}, {0x1b0b380?, 0xc0004ce280})
	/home/rst/tmp/libpod/vendor/google.golang.org/protobuf/reflect/protoregistry/registry.go:56 +0x1ee
google.golang.org/protobuf/reflect/protoregistry.(*Files).RegisterFile(0xc0001a8678, {0x1b204c8?, 0xc0000fc000?})
	/home/rst/tmp/libpod/vendor/google.golang.org/protobuf/reflect/protoregistry/registry.go:130 +0x39c
google.golang.org/protobuf/internal/filedesc.Builder.Build({{0x153c2e0, 0x34}, {0x25a1a80, 0x100, 0x100}, 0x0, 0x1, 0x0, 0x0, {0x1b10fd0, ...}, ...})
	/home/rst/tmp/libpod/vendor/google.golang.org/protobuf/internal/filedesc/build.go:112 +0x1d6
google.golang.org/protobuf/internal/filetype.Builder.Build({{{0x153c2e0, 0x34}, {0x25a1a80, 0x100, 0x100}, 0x0, 0x1, 0x0, 0x0, {0x0, ...}, ...}, ...})
	/home/rst/tmp/libpod/vendor/google.golang.org/protobuf/internal/filetype/build.go:138 +0x19d
github.com/checkpoint-restore/go-criu/v6/crit/images.file_sa_proto_init()
	/home/rst/tmp/libpod/vendor/github.com/checkpoint-restore/go-criu/v6/crit/images/sa.pb.go:190 +0x198
github.com/checkpoint-restore/go-criu/v6/crit/images.file_core_proto_init()
	/home/rst/tmp/libpod/vendor/github.com/checkpoint-restore/go-criu/v6/crit/images/core.pb.go:1109 +0x6f
github.com/checkpoint-restore/go-criu/v6/crit/images.init.12()
	/home/rst/tmp/libpod/vendor/github.com/checkpoint-restore/go-criu/v6/crit/images/core.pb.go:1095 +0x17
path is /home/rst/tmp/libpod/.coverage
Unable to read coverage file cmd/podman/coverprofile to combine, open cmd/podman/coverprofile: no such file or directory

This patch fixes this error by prepending the `criu-` prefix to
core.proto and so.proto.

Fixes: checkpoint-restore#94

Signed-off-by: Radostin Stoyanov <rstoyanov@fedoraproject.org>

crit/Makefile

@@ -22,9 +22,13 @@ update-proto:
 	# from other projects, the files of this repository are
 	# now registered under the package name `criu`.
 	ls ./images/*.proto | xargs sed -i '/syntax/a package criu;'
+	mv ./images/sa.proto ./images/criu-sa.proto
+	sed -i 's/sa\.proto/criu-sa\.proto/g' images/*.proto
+	mv ./images/core.proto ./images/criu-core.proto
+	sed -i 's/core\.proto/criu-core\.proto/g' images/*.proto
 
 gen-proto:
-	rm ./images/*.pb.go || true
+	rm -f ./images/*.pb.go || true
 	@protoc \
 		--proto_path=$(proto_path) \
 		--go_out=$(proto_path) \