`preserve index names` doesn't respect `quote identifiers`

[Faithfinder]

• [x] pgloader --version

  3.6.1
  

• [ ] did you test a fresh compile from the source tree?

• [x] did you search for other similar issues?

• [x] how can I reproduce the bug?

Table definition:

CREATE TABLE `test` (
  `Indexed` int(11) DEFAULT NULL,
  UNIQUE KEY `test_Indexed_IDX` (`Indexed`) USING BTREE
)

command.load

LOAD DATABASE
     FROM      mysql://root:root@localhost/test
     INTO      postgresql://root:root@localhost:5432/test

WITH quote identifiers, preserve index names

test_Indexed_IDX -> test_indexed_idx

[amvandenberg]

Ran into the same issue.

[nikolaigut]

I also have the same problem.