Fix complex blocks warning when running clippy

[git-hulk]

warning: in a `match` scrutinee, avoid complex blocks or closures with blocks; instead, move the block or closure higher and bind it with a `let`
   --> src/dialect/postgresql.rs:233:74
    |
233 |       match parser.maybe_parse(|parser| -> Result<ObjectName, ParserError> {
    |  __________________________________________________________________________^
234 | |         parser.expect_keyword(Keyword::CREATE)?;
235 | |         parser.expect_keyword(Keyword::TYPE)?;
236 | |         let name = parser.parse_object_name(false)?;
...   |
239 | |         Ok(name)
240 | |     }) {
    | |_____^
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#blocks_in_conditions
    = note: `#[warn(clippy::blocks_in_conditions)]` on by default

[coveralls]

Pull Request Test Coverage Report for Build 11588190891

Details

• 2 of 2 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.001%) to 89.38%

---

Totals
Change from base Build 11580333290:	0.001%
Covered Lines:	30415
Relevant Lines:	34029

---

💛 - Coveralls

[iffyio]

LGTM! cc @alamb

[alamb]

Thank you @git-hulk and @iffyio