This includes a small fix to ensure the parser doesn't produce an invalid
body for block parsing syntax errors, and instead produces an incomplete
result that calling applications like Terraform can still analyze.
The problem here was affecting our version-constraint-sniffing code, which
intentionally tried to find a core version constraint even if there's a
syntax error so that it can report that a new version of Terraform is a
likely cause of the syntax error. It was working in most cases, unless
it was the "terraform" block itself that contained the error, because then
we'd try to analyze a broken hcl.Block with a nil body.
This includes a new test for "terraform init" that exercises this
recovery codepath.
Martin Atkins