parser: fix LOCK clause error message

[lauhg]

What problem does this PR solve?

Fix compatibility problem about LOCK syntax

Issue: #508

MySQL Syntax:

alter_lock_option:
          LOCK_SYM opt_equal alter_lock_option_value { $$= $3; }
        ;

alter_lock_option_value:
          DEFAULT_SYM
          {
            $$= Alter_info::ALTER_TABLE_LOCK_DEFAULT;
          }
        | ident
          {
            if (is_identifier($1, "NONE"))
              $$= Alter_info::ALTER_TABLE_LOCK_NONE;
            else if (is_identifier($1, "SHARED"))
              $$= Alter_info::ALTER_TABLE_LOCK_SHARED;
            else if (is_identifier($1, "EXCLUSIVE"))
              $$= Alter_info::ALTER_TABLE_LOCK_EXCLUSIVE;
            else
            {
              my_error(ER_UNKNOWN_ALTER_LOCK, MYF(0), $1.str);
              MYSQL_YYABORT;
            }
          }
        ;

Bad SQL Case:

alter table t lock = first
alter table t lock = start
alter table t lock = commit
alter table t lock = binlog

Check List

Tests

• Unit test

[codecov]

Codecov Report

Merging #516 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #516   +/-   ##
=======================================
  Coverage   71.61%   71.61%           
=======================================
  Files          32       32           
  Lines        7736     7736           
=======================================
  Hits         5540     5540           
  Misses       1671     1671           
  Partials      525      525

Impacted Files	Coverage Δ
parser.go	70.58% <ø> (ø)	⬆️

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[codecov]

Codecov Report

Merging #516 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #516   +/-   ##
=======================================
  Coverage   71.59%   71.59%           
=======================================
  Files          32       32           
  Lines        7723     7723           
=======================================
  Hits         5529     5529           
  Misses       1670     1670           
  Partials      524      524

Impacted Files	Coverage Δ
parser.go	70.58% <ø> (ø)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update e2490d9...3e545f2. Read the comment docs.

[zier-one]

LGTM

[tangenta]

LGTM