Revert to aspectj-plugin-6.4.1
Revert to aspectj-plugin-6.4.1

There appears to be an issue with publication of aspectj plugin, so
this commit reverts to a previous working version.

See https://github.com/freefair/gradle-plugins/issues/511

spring-projects/spring-security,spring-projects/spring-security,spring-projects/spring-security,spring-projects/spring-security,spring-projects/spring-security,spring-projects/spring-security,spring-projects/spring-security