Bug#13510 "Setting password local variable changes current

password": additional fix, also make sure that a syntax error is 
returned for set names="foo" when there is no such variable or no
stored procedure.

mysql-test/r/sp-error.result

@@ -845,6 +845,8 @@ set password = 'foo1';
 select password;
 end|
 ERROR 42000: Variable 'password' must be quoted with `...`, or renamed
+set names='foo2'|
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1
 create procedure bug13510_2()
 begin
 declare names varchar(10);

mysql-test/t/sp-error.test

@@ -1233,6 +1233,10 @@ begin
   select password;
 end|
 
+# Check that an error message is sent
+--error ER_PARSE_ERROR
+set names='foo2'|
+
 --error ER_SP_BAD_VAR_SHADOW
 create procedure bug13510_2()
 begin

sql/sql_yacc.yy

@@ -7925,6 +7925,9 @@ option_value:
 	    names.length= 5;
 	    if (spc && spc->find_pvar(&names))
               my_error(ER_SP_BAD_VAR_SHADOW, MYF(0), names.str);
+            else
+              yyerror(ER(ER_SYNTAX_ERROR));
+
 	    YYABORT;
 	  }
 	| NAMES_SYM charset_name_or_default opt_collate