Fixed test case that changed when max_user_connections was made signed.

Threat ER_CONNECTION_KILLED same as ER_SERVER_SHUTDOWN in replication (to get rid of a possible warning in error log)

sql/slave.cc:
  Threat ER_CONNECTION_KILLED same as ER_SERVER_SHUTDOWN

mysql-test/suite/funcs_1/r/is_columns_mysql.result

@@ -197,7 +197,7 @@ NULL	mysql	user	Lock_tables_priv	21	N	NO	enum	1	3	NULL	NULL	NULL	utf8	utf8_gener
 NULL	mysql	user	max_connections	38	0	NO	int	NULL	NULL	10	0	NULL	NULL	NULL	int(11) unsigned			select,insert,update,references	
 NULL	mysql	user	max_questions	36	0	NO	int	NULL	NULL	10	0	NULL	NULL	NULL	int(11) unsigned			select,insert,update,references	
 NULL	mysql	user	max_updates	37	0	NO	int	NULL	NULL	10	0	NULL	NULL	NULL	int(11) unsigned			select,insert,update,references	
-NULL	mysql	user	max_user_connections	39	0	NO	int	NULL	NULL	10	0	NULL	NULL	NULL	int(11) unsigned			select,insert,update,references	
+NULL	mysql	user	max_user_connections	39	0	NO	int	NULL	NULL	10	0	NULL	NULL	NULL	int(11)			select,insert,update,references	
 NULL	mysql	user	Password	3		NO	char	41	41	NULL	NULL	NULL	latin1	latin1_bin	char(41)			select,insert,update,references	
 NULL	mysql	user	plugin	40		NO	char	60	60	NULL	NULL	NULL	latin1	latin1_swedish_ci	char(60)			select,insert,update,references	
 NULL	mysql	user	Process_priv	12	N	NO	enum	1	3	NULL	NULL	NULL	utf8	utf8_general_ci	enum('N','Y')			select,insert,update,references	
@@ -499,6 +499,6 @@ NULL	mysql	time_zone_transition_type	Is_DST	tinyint	NULL	NULL	NULL	NULL	tinyint(
 NULL	mysql	user	max_questions	int	NULL	NULL	NULL	NULL	int(11) unsigned
 NULL	mysql	user	max_updates	int	NULL	NULL	NULL	NULL	int(11) unsigned
 NULL	mysql	user	max_connections	int	NULL	NULL	NULL	NULL	int(11) unsigned
-NULL	mysql	user	max_user_connections	int	NULL	NULL	NULL	NULL	int(11) unsigned
+NULL	mysql	user	max_user_connections	int	NULL	NULL	NULL	NULL	int(11)
 1.0000	mysql	user	plugin	char	60	60	latin1	latin1_swedish_ci	char(60)
 1.0000	mysql	user	auth_string	text	65535	65535	utf8	utf8_bin	text

sql/slave.cc

@@ -837,6 +837,7 @@ bool is_network_error(uint errorno)
       errorno == CR_SERVER_GONE_ERROR ||
       errorno == CR_SERVER_LOST ||
       errorno == ER_CON_COUNT_ERROR ||
+      errorno == ER_CONNECTION_KILLED ||
       errorno == ER_NEW_ABORTING_CONNECTION ||
       errorno == ER_SERVER_SHUTDOWN)
     return TRUE;