Error: logging directory does not exist /var/mobile/Library/Logs/CrashReporter/DiagnosticLog/
Just go to, iOS Simulator -> Reset Content and Settings. It will restore the default settings for iOS Simulator. Remember it will also removes all apps installed in Simulator.
It's a bug in iOS. Restarting the device fixed my issue. Also check the default camera app. In my case default camera was also not working.
I was doing some programming with the file manager so it's probably related.
Exit Xcode, delete all of the DerivedData and restarted iPad, now works.
Xcode 6.2, iOS 8.2