make auth_gssapi_basic work, also in domain environment.

plugin/auth_gssapi/mysql-test/auth_gssapi/basic.result

 INSTALL SONAME 'auth_gssapi';
+Warnings:
+Note	1105	SSPI: using principal name 'localhost', mech 'Negotiate'
 CREATE USER 'GSSAPI_SHORTNAME' IDENTIFIED WITH gssapi;
 SELECT USER(),CURRENT_USER();
 USER()	CURRENT_USER()

plugin/auth_gssapi/mysql-test/auth_gssapi/basic.test

+--replace_regex /name '[a-zA-Z@.]+'/name 'localhost'/
 INSTALL SONAME 'auth_gssapi';
 
 #

plugin/auth_gssapi/sspi_server.cc

@@ -289,7 +289,7 @@ int plugin_init()
   {
     srv_principal_name= get_default_principal_name();
   }
-  my_printf_error(0, "SSPI: using principal name '%s', mech '%s'",
+  my_printf_error(ER_UNKNOWN_ERROR, "SSPI: using principal name '%s', mech '%s'",
                   ME_ERROR_LOG | ME_NOTE, srv_principal_name, srv_mech_name);
 
   ret = AcquireCredentialsHandle(