mvn helper script always exits w/1, causing mvn builds to fail

the final line in the mvn helper script in build/ attempts to shut down the zinc server.  due to the zinc server being set up w/a 30min timeout, by the time the mvn test instantiation finishes, the server times out.

this means that when the mvn script tries to shut down zinc, it returns w/an exit code of 1.  this will then automatically fail the entire build (even if the build passes).

i propose the following:

1) up the timeout to 3h

2) put some logic at the end of the script to better handle killing the zinc server

PR coming now.

srowen cloud_fan joshrosen