[go-migration] groovy application fails to add additional libraries when staged

[kiril-keranov]

When pushing a Groovy application, for example this one to Cloud Foundry using the Go-based Java buildpack, staging fails with:

[APP/PROC/WEB/0] ERR /home/vcap/app/Application.groovy: 17: unable to resolve class org.springframework.boot.SpringApplication
[APP/PROC/WEB/0] ERR @ line 17, column 1.
[APP/PROC/WEB/0] ERR import org.springframework.boot.SpringApplication
[APP/PROC/WEB/0] ERR ^
[APP/PROC/WEB/0] ERR /home/vcap/app/Application.groovy: 18: unable to resolve class org.springframework.boot.autoconfigure.SpringBootApplication
[APP/PROC/WEB/0] ERR @ line 18, column 1.
[APP/PROC/WEB/0] ERR import org.springframework.boot.autoconfigure.SpringBootApplication

The same application can be staged and run successfully with the ruby based buildpack.