Fix erlydtl warnings in 0.7.0

In 0.7.0, when `compiler_options` contains `return` or `report_warnings`,
warnings are returned by erlydtl and cannot generate beams, so it's an error.

While in 0.8.0, this bug has been fixed:
https://github.com/erlydtl/erlydtl/commit/f74b94f800bae7ab5eccd763d6d4ff064b8988e6#diff-08c5c8e12b9ecb678434d3a9faa73630

So we just need to report error in 0.7.0