Closes #218 - Stop accumulo classpath value from being shortened

Pull request for #218 
When I first saw this, I thought it may be better as a test resource.  However after a little more thought I think its  neat validating the file we expect users to start with.

Could possibly make the test fail if it sees props it did not validate.  I.e. if the test validates props A,B,C but the file contains props A,B,C,D.  This could be another issue.