Fix typo in storage README.md
Fix typo in storage README.md

s/while/for
mbrukman/gcloud-java,FirebasePrivate/google-cloud-java,mbrukman/gcloud-java,shinfan/gcloud-java,shinfan/gcloud-java,FirebasePrivate/google-cloud-java,vam-google/google-cloud-java,vam-google/google-cloud-java,FirebasePrivate/google-cloud-java,vam-google/google-cloud-java,mbrukman/gcloud-java,vam-google/google-cloud-java,vam-google/google-cloud-java,FirebasePrivate/google-cloud-java,shinfan/gcloud-java,FirebasePrivate/google-cloud-java,mbrukman/gcloud-java,vam-google/google-cloud-java,shinfan/gcloud-java,shinfan/gcloud-java