use app_bundle_dsym() to detect dSYM path

We plan to change a name of dSYM path to fix http://hipbyte.myjetbrains.com/youtrack/issue/RM-487
(We changed same code in motion-testflight at https://github.com/HipByte/motion-testflight/commit/67a844b64a4606d23f240ae2a47a2d0b6dcbe979)

Thank you.