Writes debug files by default to a hard-coded location and doesn't remove them

[deadok22]

Since #147, the library writes some debug information to a /var/tmp/dd-opentracing-cpp/startup_options-*.json file on startup. This is problematic:

• The users risk running out of disk in environments where the processes consuming the library are started frequently (this did actually happen in my setup with NGINX Ingress Controller)
• The hard-coded location is bad for portability

I believe this output should be turned off by default and its destination should be made configurable.

[deadok22]

Just noticed the code in question was commented out in #150, so this report may be obsolete.

[cgilmour]

Thanks for reporting this @deadok22, and although this had good intentions (it's very useful information for support teams), I agree it's problematic and it did later get removed. As other projects update, it'll stop being a problem.

The code should have been removed instead of commented out - an oversight on my part. Let's leave this issue open until that has been cleaned up.

[dgoffredo]

The most recent release of the ingress controller includes this version of the datadog tracer, which includes Caleb's fix.

I don't know how to upgrade an ingress controller, but doing so will likely resolve this issue.