Make build script exit with non-zero status when sniff fails.
Merge pull request #330 from bantu/phing-sniff-fail

Make build script exit with non-zero status when sniff fails.

* bantu/phing-sniff-fail:
  Make build script exit with non-zero status when sniff fails.
Merge branch 'master' into php5

* master:
  Make build script exit with non-zero status when sniff fails.