Once the content type is deleted the variables remains in the database

Problem/Motivation

If you delete a content type his variables:

node_revision_delete_number_CONTENT-TYPE-MACHINE-NAME
node_revision_delete_track_CONTENT-TYPE-MACHINE-NAME

Remains in the database.

Proposed resolution

Eliminate the variables once the content type is deleted

Remaining tasks

None.

User interface changes

None.

API changes

None.

Data model changes

None.