* Fix invalid MIME formatting in multipart cloudinit userdata
Per https://tools.ietf.org/html/rfc822#appendix-B.2, MIME headers and Body need to be separated by two new lines (or CRLFs in this case).
The email parser in python can handle this which is what cloud-init uses but this bug causes problems if you try to parse the multipart message by languages other than python.
* Fix test cases
Fixes an uncaught panic during an interface cast in the `template_cloudinit_config` data source.
Fixes: #13572
```
$ make test TEST=./builtin/providers/template TESTARGS="-v -run=TestRender_handlePanic"
==> Checking that code complies with gofmt requirements...
==> Checking AWS provider for unchecked errors...
==> NOTE: at this time we only look for uncheck errors in the AWS package
go generate $(go list ./... | grep -v /terraform/vendor/)
2017/04/12 10:46:33 Generated command/internal_plugin_list.go
go test -i ./builtin/providers/template || exit 1
echo ./builtin/providers/template | \
xargs -t -n4 go test -v -run=TestRender_handlePanic -timeout=60s -parallel=4
go test -v -run=TestRender_handlePanic -timeout=60s -parallel=4 ./builtin/providers/template
=== RUN TestRender_handlePanic
--- PASS: TestRender_handlePanic (0.00s)
PASS
ok github.com/hashicorp/terraform/builtin/providers/template 0.028s
```
This dep was meant as a stopgap for a patch in the stdlib of Go which I
wrote.
The patch was released in Go 1.7. We can now remove my fork and go back
to the stdlib
The template resources don't actually need to retain any state, so they
are good candidates to be data sources.
This includes a few tweaks to the acceptance tests -- now configured to
run as unit tests -- since it seems that they have been slightly broken
for a while now. In particular, the "update" cases are no longer tested
because updating is not a meaningful operation for a data source.
Devin Lundberg