fix for the bug #2786 incorrect precedence for XOR operator

mysql-test/r/func_test.result

@@ -46,6 +46,9 @@ select 3 ^ 11, 1 ^ 1, 1 ^ 0, 1 ^ NULL, NULL ^ 1;
 select 1 XOR 1, 1 XOR 0, 0 XOR 1, 0 XOR 0, NULL XOR 1, 1 XOR NULL, 0 XOR NULL;
 1 XOR 1	1 XOR 0	0 XOR 1	0 XOR 0	NULL XOR 1	1 XOR NULL	0 XOR NULL
 0	1	1	0	NULL	NULL	NULL
+select 1 like 2 xor 2 like 1;
+1 like 2 xor 2 like 1
+0
 create table t1 (a int);
 insert t1 values (1);
 select * from t1 where 1 xor 1;

mysql-test/t/func_test.test

@@ -17,6 +17,7 @@ select 2 in (3,2,5,9,5,1),"monty" in ("david","monty","allan"), 1.2 in (1.4,1.2,
 select -1.49 or -1.49,0.6 or 0.6;
 select 3 ^ 11, 1 ^ 1, 1 ^ 0, 1 ^ NULL, NULL ^ 1;
 select 1 XOR 1, 1 XOR 0, 0 XOR 1, 0 XOR 0, NULL XOR 1, 1 XOR NULL, 0 XOR NULL;
+select 1 like 2 xor 2 like 1;
 
 create table t1 (a int);
 insert t1 values (1);

sql/sql_yacc.yy

@@ -478,7 +478,7 @@ bool my_yyoverflow(short **a, YYSTYPE **b,int *yystacksize);
 %token  CIPHER_SYM
 
 %left   SET_VAR
-%left	OR_OR_CONCAT OR
+%left	OR_OR_CONCAT OR XOR
 %left	AND
 %left	BETWEEN_SYM CASE_SYM WHEN_SYM THEN_SYM ELSE
 %left	EQ EQUAL_SYM GE GT_SYM LE LT NE IS LIKE REGEXP IN_SYM
@@ -488,7 +488,6 @@ bool my_yyoverflow(short **a, YYSTYPE **b,int *yystacksize);
 %left	'-' '+'
 %left	'*' '/' '%'
 %left	NEG '~'
-%left   XOR
 %left   '^'
 %right	NOT
 %right	BINARY