Remove "Could not retrieve users for UserCF" error message during issue creation

2013-05-23 15:14:28,316 http-2990-8 INFO admin 914x6123x1 wu0ymg 172.28.13.175 /rest/api/latest/user/assignable/multiProjectSearch [jira.security.type.UserCF] Could not retrieve users for UserCF 'customfield_10000' since provided PermissionContext has no issue.

/**
     * Get user specified by the Custom Field
     *
     * @param ctx           permission context
     * @param customFieldId eg. 'customfield_10000'
     * @return the set of users stored in the given custom field in the given context; an empty set is returned if the
     * context could not provide values (i.e. there was no issue specified).
     */
    @Override
    public Set<User> getUsers(PermissionContext ctx, String customFieldId)
    {
        // JRA-15063: just return EMPTY SET (like GroupCF does) because throwing an IllegalArgumentException is unnecessary.
        if (ctx.getIssue() == null)
        {
            log.info("Could not retrieve users for UserCF '" + customFieldId + "' since provided PermissionContext has no issue.");
            return Collections.EMPTY_SET;
        }
        Issue issue = ctx.getIssue();
        FieldManager fieldManager = getFieldManager();
        CustomField field = fieldManager.getCustomField(customFieldId);
        return convertToValueSet(getValuesFromIssue(field, issue));
    }

 * Represents the context in which a permission evaluation is to be made.
 * Permission requests are of the form: subject, verb, object (eg. "User fred wishes to comment on ABC-123"), where:
 * subject = User object
 * verb = permission Id
 * object = Issue, project etc.
 * A PermissionContext encapsulates the object.