Improve test script

[estadtherr]

This change makes two improvements to the test/test.sh script:

1. Remove a test file that was left in the test bucket before trying to remove the test bucket
2. Track counts of failures of individual tests, and make the exit status of the test script reflect success or failure

These changes enable an automated build to depend on unit test success/failure.

[bji]

I am currently travelling and will evaluate this pull request when I return in one week. Thank you!

[bji]

Thank you!