Update MysqlRecordProperty model
Update MysqlRecordProperty model

This commit fixes the python model for mysql record property according
to the changes in:
cbaf4e86c4409735a8f011f5a8f801a34278c21c

Other modification in this commit are to match the model to the current
state of the database. These changes are:
- Remove fulltext index declaration to match the actual database model
- Change engine to default.

AleksNeStu/ggrc-core,AleksNeStu/ggrc-core,AleksNeStu/ggrc-core,AleksNeStu/ggrc-core