Honor bccsp.sw.filekeystore.keystore in server config

[wieghx]

Type of change

• Bug fix

Description

fabric-ca-server-config.yaml documents:

bccsp:
  sw:
    filekeystore:
      keystore: msp/keystore

Viper/mapstructure binds keystore to the field name KeyStorePath, so the value was dropped and ConfigureBCCSP always defaulted to msp/keystore.

After unmarshal, copy bccsp.sw.filekeystore.keystore onto FileKeystoreOpts.KeyStorePath when that field is still empty. This is local to fabric-ca and does not change global decoder tags or fabric-lib-go.

Additional details

go test ./lib/ -count=1 -run TestUnmarshalConfig
go test ./util/ -count=1 -run 'TestConfigureBCCSPKeepsCustomKeyStorePath|TestInitBCCSP'

Related issues

#515

This PR was written in part with the assistance of generative AI.

[wieghx]

FVT intermediateca_test.sh failed on postgres admin reenroll with 401 Failed to get user.

That request hit a cached LDAP connection that returned unable to read LDAP response packet: EOF. The pathlen-0 policy check, enroll, and the later mysql pass all succeeded; BCCSP keystore paths stayed at $HOME/msp/keystore.

Pushed an empty commit to retrigger CI.