PG: error raised for field with default value like 'foo'::text

[Even Rouault]

A 'ERROR 1: Incorrectly quoted string literal' error is raised

[Even Rouault]

In 38134:

PG: avoid errors with field default expressions like 'foo'::text (fixes #6872)

[Even Rouault]

In 38135:

PG: avoid errors with field default expressions like 'foo'::text (fixes #6872)

[Even Rouault]

In 38136:

PG: avoid errors with field default expressions like 'foo'::text (fixes #6872)