Fix broken sr_stacktrace_parse

Did not work for any other crash types than "core" due to the wrong
function being called.

Signed-off-by: Martin Milata <mmilata@redhat.com>
Signed-off-by: Richard Marko <rmarko@redhat.com>
Use build id when comparing core frames for distance

The function names might not be known and the fingerprints are
unreliable. On the other hand, we should always have build ID, which is
also very reliable.

Fixes #91.

Signed-off-by: Martin Milata <mmilata@redhat.com>
Signed-off-by: Richard Marko <rmarko@redhat.com>