This reomves a dependency on gogo/protobuf.
```
$ go test -count=1 github.com/cloudflare/cfssl/{auth,certdb,certdb/dbconf,certdb/sql,config,crypto/pkcs7,csr,errors,helpers,helpers/derhelpers,info,log,ocsp,ocsp/config,signer,signer/local}
ok github.com/cloudflare/cfssl/auth 0.032s
? github.com/cloudflare/cfssl/certdb [no test files]
ok github.com/cloudflare/cfssl/certdb/dbconf 0.005s
ok github.com/cloudflare/cfssl/certdb/sql 0.430s
ok github.com/cloudflare/cfssl/config 0.018s
? github.com/cloudflare/cfssl/crypto/pkcs7 [no test files]
ok github.com/cloudflare/cfssl/csr 8.343s
ok github.com/cloudflare/cfssl/errors 0.012s
ok github.com/cloudflare/cfssl/helpers 0.125s
ok github.com/cloudflare/cfssl/helpers/derhelpers 0.007s
? github.com/cloudflare/cfssl/info [no test files]
ok github.com/cloudflare/cfssl/log 0.018s
ok github.com/cloudflare/cfssl/ocsp 0.093s
? github.com/cloudflare/cfssl/ocsp/config [no test files]
ok github.com/cloudflare/cfssl/signer 0.016s
ok github.com/cloudflare/cfssl/signer/local 0.621s
```
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