[Backup cleanup] remove call to no-op method setBackupProvisioned

Bug: 120120742

Test: 1) atest RunBackupFrameworksServicesRoboTests
2) atest $(find \
frameworks/base/services/tests/servicestests/src/com/android/server/backup \
-name '*Test.java')

Change-Id: I9d6d312f32d79646384adb60726e4c12ee12c052
1 file changed