Curl by default does not report errors by setting the error code.
As the upload can fail through several conditions (e.g. the rate
limit, leading to unauthorized access) we should indicate this
information in Travis CI.

To improve upon the behavior, use `--write-out=%{http_code}` to
write out the HTTP code in addition to the received body and
return an error if the code does not equal 201.

When posting our instrumented build results to Coverity we have
to include sensitive information, in particular our authorization
token. Currently we use an unencrypted channel to post this
information, leading to the token being transferred in plain.

Fix this by using a secured connection instead.

Coverity currently lists a lot of errors with regard to
GITERR_CHECK_ALLOC causing resource leaks. We know this macro is
only invoked when we want to abort because we are out of memory.

Coverity allows for overriding the default model where we know
that certain functions guarantee a desired behavior. The
user_nodefs.h is used to override the behavior of macros.
Re-define GITERR_CHECK_ALLOC inside of it to specify its abort
nature.