Fix duplicate camelCase properties

[terax6669]

• Type: bug fix

In raising this pull request, I confirm the following (please check boxes):

• I have read and understood the Contributing Guidelines
• I have checked that another pull request for this purpose does not exist
• I wrote some tests for this PR

Small description of change:
Regenerating an existing model with --force duplicates camelized properties.

[Jeckerson]

Could you check current error?
https://travis-ci.org/github/phalcon/phalcon-devtools/jobs/665252193#L833

[terax6669]

Calling empty on a boolean value is almost certainly unintended
I guess he has a problem with the fact that this is an array of bools, but that'd mean that the previous code had the same error 😝

[jenovateurs]

@terax6669, I fixed some errors with travis, maybe your code will be pass after you pull the last version of the code.

[Jeckerson]

@terax6669 Can you rebase with latest changes in 4.0.x branch and see if CI errors gone?