count DATA cells with stream ID 0 as delivered for SENDME purposes

Found while investigating 8093, but probably not the cause of it,
since this bug would result in us sending too few SENDMEs, not in us
receiving SENDMEs unexpectedly.

Bugfix on the fix for 7889, which has appeared in 0.2.4.10-alpha, but
not yet in any released 0.2.3.x version.
Bulletproof our 11246 fix a little, based on recommendation from andrea.
put the right trac ticket number in changes file
Improved diagnostic log for bug 8387.

When we find a stranded one-hop circuit, log whether it is dirty,
log information about any streams on it, and log information about
connections they might be linked to.
Merge remote-tracking branch 'public/more_bug8387_diagnosis'
Merge remote-tracking branch 'public/not_bug8093'