I encountered the same problem today with the same exact error message when trying to submit our app (using Xcode 7 beta 5) but instead of the instabug.bundle bit, it was for me TencentOpenApi_IOS_Bundle.bundle.
I solved the problem by finding the named bundle in the project then – just as the error message suggests – edited the Info.plist that is in the bundle by removing the CFBundleExecutable key. The CFBundlePackageType key was already set to BNDL so I didn’t touch it.
After these changes I did Product > Clean and then had no problem submitting the app to the App store.