docs: Android examples moved for sed in RELEASING.md
docs: Android examples moved for sed in RELEASING.md

examples/android/app/build.gradle is now
examples/android/helloworld/app/build.gradle and
examples/android/routeguide/app/build.gradle.

Since the number of files is getting a bit long, move it to a variable.
rmichela/grpc-java,carl-mastrangelo/grpc-java,elandau/grpc-java,rmichela/grpc-java,pieterjanpintens/grpc-java,zpencer/grpc-java,grpc/grpc-java,zhangkun83/grpc-java,pieterjanpintens/grpc-java,carl-mastrangelo/grpc-java,simonhorlick/grpc-java,stanley-cheung/grpc-java,simonhorlick/grpc-java,zpencer/grpc-java,carl-mastrangelo/grpc-java,rmichela/grpc-java,simonhorlick/grpc-java,zpencer/grpc-java,rmichela/grpc-java,stanley-cheung/grpc-java,anuraaga/grpc-java,dapengzhang0/grpc-java,dapengzhang0/grpc-java,elandau/grpc-java,zhangkun83/grpc-java,anuraaga/grpc-java,dapengzhang0/grpc-java,pieterjanpintens/grpc-java,dapengzhang0/grpc-java,nmittler/grpc-java,nmittler/grpc-java,simonhorlick/grpc-java,elandau/grpc-java,zhangkun83/grpc-java,ejona86/grpc-java,nmittler/grpc-java,stanley-cheung/grpc-java,stanley-cheung/grpc-java,grpc/grpc-java,zpencer/grpc-java,elandau/grpc-java,carl-mastrangelo/grpc-java,zhangkun83/grpc-java,anuraaga/grpc-java,ejona86/grpc-java,pieterjanpintens/grpc-java,grpc/grpc-java,ejona86/grpc-java,grpc/grpc-java,ejona86/grpc-java