Remove redundant modifiers from ERC721 safeTransferFrom (#1029)

[abandeali1]

Fixes #1029

🚀 Description

Removes modifiers from ERC721BasicToken.sol. onlyOwnerOf was not actually being used, and canTransfer has been removed for efficiency reasons.

• 📘 I've reviewed the OpenZeppelin Contributor Guidelines
• ✅ I've added tests where applicable to test my new functionality.
• 📖 I've made sure that my contracts are well-documented.
• 🎨 I've run the JS/Solidity linters and fixed any issues (npm run lint:all:fix).

[frangio]

Thanks @abandeali1! I think this is an acceptable optimization.