Updating a RemotePrincipal does not add new attributes to LDAP

Reproduce bug:

1. RemotePrincipal created without givenName attribute via Crowd Console in an LDAP directory
2. Attribute givenName is later added via the Crowd Console

The "givenName" attribute is not added to the principal even though it is a supported/mapped LDAP attribute.

This will also affect methods on the SecurityServerClient such as updatePrincipalAttribute/removeAttributeFromPrincipal, and in turn affects integration with applications that first create an almost blank user and then populate the user's properties (eg. creating users via Confluence).