Revert "Bug 971648: Add warning message if there is no"

This reverts commit 70f3a23da3a89e00afda4eb3573de656b10d8ea0.
Revert "Bug 971648: Add warning message if there is no manifest.webapp"

This reverts commit 3c7e468f78843992a892ff036f470ceb260c6a07.