srm-client: delegate by default for https 3rd-party transfers

By default, the srm-client srmcp command will delegate only
when it thinks it makes sense.  Unfortunately, it makes the
wrong decision for http and https transfers: mistakenly
delegating for the former and not for the latter.

This patch fixes this.  It also modifies a variable name to
make more sense.

Target: master
Patch: https://rb.dcache.org/r/7393/
Acked-by: Gerd Behrmann
Request: 2.10
Require-notes: yes
Require-book: no