Use the `Kernel#system` command to allow us to stop when the exit code of the command is non-zero.  This also has the advantage of outputting the command to STDOUT.  Also cleaning up a lot of duplication
Use the `Kernel#system` command to allow us to stop when the exit code of the command is non-zero.  This also has the advantage of outputting the command to STDOUT.  Also cleaning up a lot of duplication

subvertallchris/neo4j-core,subvertallchris/neo4j-core,neo4jrb/neo4j-core,neo4jrb/neo4j-core