Submission scripts are broken on ec2 clusters started with spark-ec2 with private IP's

I've started some fresh clusters using spark-ec2 on VPC's that only have private IP addresses. This worked fine with some PR's I made to spark-ec2 against 1.3 that are now in 1.4. However, now all job submission is broken.

./bin/pyspark and ./bin/sparkR work fine. However, ./bin/spark-submit, ./bin/spark-class, ./bin/spark-shell, and ./bin/spark-sql are all broken. They return immediately to the command line with no error and no output.

I've tracked it down to some environment stuff in this diff:

https://github.com/amplab/spark-ec2/commit/b21512ef553e382b1bdde48fcb0c7b23a5187616

I don't entirely understand the source (related to next sourcing of bash scripts and environment stuff) but I have a fix that I'll submit in a bit.