remove X509LDAPCertStoreSpi.java and references

X509LDAPCertStoreSpi.java imports classes from the javax.naming name space, which is not included in Android. This leads to lint errors when checking projects which include SC-prov. As SC is aimed at Android, we
might just as well just leave this class out.

An alternative might be creating a dummy class, which throws UnsupportedOperationException or a CertStoreException.